(maint) Update commit check

This commit updates the commits Rake check to include commit summaries
that begin with the Puppet Agent (PA) Jira project and removes
references to a non-existent CONTRIBUTION.md.

rakelib/commits.rake

@@ -1,4 +1,4 @@
-desc "verify that commit messages match CONTRIBUTING.md requirements"
+desc "verify that commit summaries are properly formatted"
 task(:commits) do
   # This rake task looks at the summary from every commit from this branch not
   # in the branch targeted for a PR.
@@ -7,11 +7,10 @@ task(:commits) do
   %x{git log --no-merges --pretty=%s #{commit_range}}.each_line do |commit_summary|
     # This regex tests for the currently supported commit summary tokens.
     # The exception tries to explain it in more full.
-    if /^Release prep|\((maint|packaging|doc|docs|modules-\d+)\)|revert/i.match(commit_summary).nil?
-      raise "\n\n\n\tThis commit summary didn't match CONTRIBUTING.md guidelines:\n" \
-        "\n\t\t#{commit_summary}\n" \
-        "\tThe commit summary (i.e. the first line of the commit message) should start with one of:\n"  \
-        "\t\t(MODULES-<digits>) # this is most common and should be a ticket at tickets.puppet.com\n" \
+    if /^Release prep|\((maint|packaging|doc|docs|modules|pa-\d+)\)|revert/i.match(commit_summary).nil?
+      raise "\n\n\n\tPlease make sure that your commit summary (i.e. the first line of the commit message) starts with one of the following:\n"  \
+        "\t\t(PA-<digits>)\n" \
+        "\t\t(MODULES-<digits>)\n" \
         "\t\t(docs)\n" \
         "\t\t(docs)(DOCUMENT-<digits>)\n" \
         "\t\t(packaging)\n"