(MODULES-4604) move name validation in mysql_grant type

Users are running into an issue where \`puppet resource mysql_grant\` fails because there is a global name validation using properties that only exist in a compiled catalog and not in the naked type that is instantiated during a \`puppet resource\` run. This moves name validation into the \`name\`  parameter in the mysql_grant type. See also #522

Author: eputnam

lib/puppet/type/mysql_grant.rb

@@ -34,12 +34,15 @@ def initialize(*args)
     fail('PROXY must be the only privilege specified.') if Array(self[:privileges]).count > 1 and Array(self[:privileges]).include?('PROXY')
     fail('table parameter is required.') if self[:ensure] == :present and self[:table].nil?
     fail('user parameter is required.') if self[:ensure] == :present and self[:user].nil?
-    fail('name must match user and table parameters') if self[:name] != "#{self[:user]}/#{self[:table]}"
   end
 
   newparam(:name, :namevar => true) do
     desc 'Name to describe the grant.'
 
+    validate do |value|
+      fail("name must match user@host/table format. got #{value} instead") unless value.match(/^.*@.*\/.*$/)
+    end
+
     munge do |value|
       value.delete("'")
     end