Guard against undef $puppet_agent::collection

If `$puppet_agent::collection` was undef, then the regex match would result in an
error:

    $ bundle exec puppet apply -e '$foo = undef if $foo =~ /core/ { }'
    Error: Evaluation Error: Left match operand must result in a String value. Got an Undef Value.

Author: joshcooper

Diff for: manifests/osfamily/debian.pp

@@ -66,7 +66,7 @@
           ensure   => absent,
           priority => '90',
         }
-      } elsif $puppet_agent::collection =~ /core/ {
+      } elsif $puppet_agent::collection and $puppet_agent::collection =~ /core/ {
         $source = 'https://apt-puppetcore.puppet.com'
       } else {
         $source = $puppet_agent::apt_source

Diff for: manifests/osfamily/redhat.pp

@@ -60,7 +60,7 @@
     } else {
       if $puppet_agent::collection == 'PC1' {
         $source = "${puppet_agent::yum_source}/${platform_and_version}/${puppet_agent::collection}/${puppet_agent::arch}"
-      } elsif $puppet_agent::collection =~ /core/ {
+      } elsif $puppet_agent::collection and $puppet_agent::collection =~ /core/ {
         $_collection = regsubst($puppet_agent::collection, /core/, '')
         $source = "https://yum-puppetcore.puppet.com/${_collection}/${platform_and_version}/${puppet_agent::arch}"
       } else {

Diff for: manifests/osfamily/suse.pp

@@ -50,7 +50,7 @@
     } else {
       if $puppet_agent::collection == 'PC1' {
         $source = "${puppet_agent::yum_source}/sles/${facts['os']['release']['major']}/${puppet_agent::collection}/${puppet_agent::arch}"
-      } elsif $puppet_agent::collection =~ /core/ {
+      } elsif $puppet_agent::collection and $puppet_agent::collection =~ /core/ {
         $_collection = regsubst($puppet_agent::collection, /core/, '')
         $source = "https://yum-puppetcore.puppet.com/${_collection}/sles/${facts['os']['release']['major']}/${puppet_agent::arch}"
       } else {

Diff for: manifests/osfamily/windows.pp

@@ -25,7 +25,7 @@
   } else {
     if $puppet_agent::collection == 'PC1' {
       $source = "${puppet_agent::windows_source}/windows/${puppet_agent::package_name}-${puppet_agent::prepare::package_version}-${puppet_agent::arch}.msi"
-    } elsif $puppet_agent::collection =~ /core/ {
+    } elsif $puppet_agent::collection and $puppet_agent::collection =~ /core/ {
       $source = 'https://artifacts-puppetcore.puppet.com/v1/download'
       $destination_name = "${puppet_agent::package_name}-${puppet_agent::prepare::package_version}-${puppet_agent::arch}.msi"
     } else {

Diff for: manifests/prepare/package.pp

@@ -38,7 +38,7 @@
     $mode = '0644'
   }
 
-  if $puppet_agent::collection =~ /core/ and $facts['os']['family'] =~ /windows/ {
+  if $puppet_agent::collection and $puppet_agent::collection =~ /core/ and $facts['os']['family'] =~ /windows/ {
     $download_username = getvar('puppet_agent::username', 'forge-key')
     $download_password = unwrap(getvar('puppet_agent::password'))