[ReleasePR imagebuilder] update 2020-02-14 (#1528)

Create to sync Azure/azure-rest-api-specs#13159
[ReCreate this PR](https://github.com/azure-resource-manager-schemas/compare/master...AzureSDKAutomation:sdkAuto/imagebuilder?expand=1)

Author: msftbot[bot]

schemas/2018-02-01-preview/Microsoft.VirtualMachineImages.json

@@ -324,4 +324,4 @@
       "properties": {}
     }
   }
-}
+}

schemas/2019-02-01-preview/Microsoft.VirtualMachineImages.json

@@ -459,4 +459,4 @@
       "description": "Distribute via VHD in a storage account."
     }
   }
-}
+}

schemas/2019-05-01-preview/Microsoft.VirtualMachineImages.json

@@ -622,4 +622,4 @@
       "description": "Describes the virtual machine used to build, customize and capture images"
     }
   }
-}
+}

schemas/2020-02-14/Microsoft.VirtualMachineImages.json

@@ -172,6 +172,7 @@
         },
         "sha256Checksum": {
           "type": "string",
+          "default": "",
           "description": "SHA256 checksum of the file provided in the sourceUri field above"
         },
         "sourceUri": {
@@ -305,7 +306,7 @@
         },
         "version": {
           "type": "string",
-          "description": "Image version from the [Azure Gallery Images](https://docs.microsoft.com/en-us/rest/api/compute/virtualmachineimages)."
+          "description": "Image version from the [Azure Gallery Images](https://docs.microsoft.com/en-us/rest/api/compute/virtualmachineimages). If 'latest' is specified here, the version is evaluated when the image build takes place, not when the template is submitted. Specifying 'latest' could cause ROUNDTRIP_INCONSISTENT_PROPERTY issue which will be fixed."
         }
       },
       "required": [
@@ -333,7 +334,8 @@
         "runAsSystem": {
           "oneOf": [
             {
-              "type": "boolean"
+              "type": "boolean",
+              "default": false
             },
             {
               "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
@@ -344,7 +346,8 @@
         "runElevated": {
           "oneOf": [
             {
-              "type": "boolean"
+              "type": "boolean",
+              "default": false
             },
             {
               "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
@@ -358,6 +361,7 @@
         },
         "sha256Checksum": {
           "type": "string",
+          "default": "",
           "description": "SHA256 checksum of the power shell script provided in the scriptUri field above"
         },
         "type": {
@@ -394,7 +398,8 @@
             {
               "type": "integer",
               "minimum": 0,
-              "maximum": 960
+              "maximum": 960,
+              "default": "0"
             },
             {
               "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
@@ -492,7 +497,8 @@
         "excludeFromLatest": {
           "oneOf": [
             {
-              "type": "boolean"
+              "type": "boolean",
+              "default": false
             },
             {
               "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
@@ -590,6 +596,7 @@
         },
         "sha256Checksum": {
           "type": "string",
+          "default": "",
           "description": "SHA256 checksum of the shell script provided in the scriptUri field"
         },
         "type": {
@@ -642,7 +649,8 @@
           "oneOf": [
             {
               "type": "integer",
-              "minimum": 0
+              "minimum": 0,
+              "default": "0"
             },
             {
               "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
@@ -652,6 +660,7 @@
         },
         "vmSize": {
           "type": "string",
+          "default": "",
           "description": "Size of the virtual machine used to build, customize and capture images. Omit or specify empty string to use the default (Standard_D1_v2)."
         },
         "vnetConfig": {
@@ -747,4 +756,4 @@
       "description": "Virtual Network configuration."
     }
   }
-}
+}