build: update node.gyp to reference gypfiles/v8.gyp

Refs: v8/v8@f9934aa
Fixes: nodejs#36

node.gypi

@@ -38,12 +38,12 @@
       ],
     }],
     [ 'node_enable_d8=="true"', {
-      'dependencies': [ 'deps/v8/src/d8.gyp:d8' ],
+      'dependencies': [ 'deps/v8/gypfiles/d8.gyp:d8' ],
     }],
     [ 'node_use_bundled_v8=="true"', {
       'dependencies': [
-        'deps/v8/src/v8.gyp:v8',
-        'deps/v8/src/v8.gyp:v8_libplatform'
+        'deps/v8/gypfiles/v8.gyp:v8',
+        'deps/v8/gypfiles/v8.gyp:v8_libplatform'
       ],
     }],
     [ 'node_use_v8_platform=="true"', {
@@ -93,7 +93,7 @@
       'defines': [ 'NODE_NO_BROWSER_GLOBALS' ],
     } ],
     [ 'node_use_bundled_v8=="true" and v8_postmortem_support=="true"', {
-      'dependencies': [ 'deps/v8/src/v8.gyp:postmortem-metadata' ],
+      'dependencies': [ 'deps/v8/gypfiles/v8.gyp:postmortem-metadata' ],
       'conditions': [
         # -force_load is not applicable for the static library
         [ 'force_load=="true"', {