Fix Alpine and Mariner /etc/hosts templates

Revert the changes I introduced with #1084, these had the side-effect
of causing "hostname" problems. Fixes #4771.

Also remove the "::1 {{fqdn}} {{hostname}}" entry as this this being
results in strange behaviour with both Busybox "hostname -i" (returns
"127.0.0.1", or "127.0.0.1 A.B.C.D" if an additional non-loopback IP
entry in /etc/hosts) and Coreutils "hostname -i" (returns "::1" in
both situations), commands whereas if the "::1" entry is removed then
both Busybox and Coreutils behave the the same fashion returning
"127.0.0.1" or "127.0.0.1 A.B.C.D" as appropriate.

Also correct hosts.mariner.tmpli file it was not valid (every line
was prefixed with "+").

templates/hosts.alpine.tmpl

@@ -13,13 +13,12 @@ you need to add the following to config:
 #     /etc/cloud/cloud.cfg or cloud-config from user-data
 #
 # The following lines are desirable for IPv4 capable hosts
-127.0.1.1 {{hostname}} {{fqdn}}
-127.0.0.1 localhost localhost.localdomain
-127.0.0.1 localhost4 localhost4.localdomain4
+127.0.0.1 localhost.localdomain localhost
+127.0.0.1 localhost4.localdomain4 localhost4
+127.0.1.1 {{fqdn}} {{hostname}}
 
 # The following lines are desirable for IPv6 capable hosts
-::1 {{hostname}} {{fqdn}}
-::1 localhost6 localhost6.localdomain6
+::1 localhost6.localdomain6 localhost6
 
 ff02::1 ip6-allnodes
 ff02::2 ip6-allrouters

templates/hosts.mariner.tmpl

@@ -1,22 +1,22 @@
-+## template:jinja
-+{#
-+This file /etc/cloud/templates/hosts.mariner.tmpl is only utilized
-+if enabled in cloud-config.  Specifically, in order to enable it
-+you need to add the following to config:
-+  manage_etc_hosts: True
-+-#}
-+# Your system has configured 'manage_etc_hosts' as True.
-+# As a result, if you wish for changes to this file to persist
-+# then you will need to either
-+# a.) make changes to the master file in /etc/cloud/templates/hosts.mariner.tmpl
-+# b.) change or remove the value of 'manage_etc_hosts' in
-+#     /etc/cloud/cloud.cfg or cloud-config from user-data
-+#
-+# The following lines are desirable for IPv4 capable hosts
-+127.0.0.1 {{fqdn}} {{hostname}}
-+127.0.0.1 localhost.localdomain localhost
-+127.0.0.1 localhost4.localdomain4 localhost4
-+
-+# The following lines are desirable for IPv6 capable hosts
-+::1 {{fqdn}} {{hostname}}
-+::1 localhost6.localdomain6 localhost6
+## template:jinja
+{#
+This file /etc/cloud/templates/hosts.mariner.tmpl is only utilized
+if enabled in cloud-config.  Specifically, in order to enable it
+you need to add the following to config:
+  manage_etc_hosts: True
+-#}
+# Your system has configured 'manage_etc_hosts' as True.
+# As a result, if you wish for changes to this file to persist
+# then you will need to either
+# a.) make changes to the master file in /etc/cloud/templates/hosts.mariner.tmpl
+# b.) change or remove the value of 'manage_etc_hosts' in
+#     /etc/cloud/cloud.cfg or cloud-config from user-data
+#
+# The following lines are desirable for IPv4 capable hosts
+127.0.0.1 {{fqdn}} {{hostname}}
+127.0.0.1 localhost.localdomain localhost
+127.0.0.1 localhost4.localdomain4 localhost4
+
+# The following lines are desirable for IPv6 capable hosts
+::1 {{fqdn}} {{hostname}}
+::1 localhost6.localdomain6 localhost6