add a workaround for rabbitmq_vhost when running with --noop or --tags

This fixes the error:
Error: Could not prefetch rabbitmq_vhost provider 'rabbitmqctl': Command rabbitmqctl is missing

The problem, and the workaround, are the same as that described in
commit 8a3a27a, "add a workaround for
running with --noop or --tags".

This is necessary because the original workaround is for
rabbitmqctl_list(), whereas rabbitmq_version() calls rabbitmqctl()
directly.

Other callers of rabbitmq_version() should not need this workaround,
since they are not run in a state where rabbitmq itself is not yet
installed.

Author: bugfood

lib/puppet/provider/rabbitmq_vhost/rabbitmqctl.rb

@@ -19,6 +19,11 @@ def self.prefetch(resources)
   # we only deal with vhost metadata >= version 3.11.0
   def self.supports_metadata?
     Puppet::Util::Package.versioncmp(rabbitmq_version, '3.11') >= 0
+  rescue Puppet::MissingCommand
+    # See comment on the definition of rabbitmqctl_list in rabbitmqctl_cli.rb;
+    # the same rationale applies here.
+    Puppet.debug('supports_metadata?: rabbitmqctl command not found; assuming rabbitmq is not installed')
+    false
   end
 
   def supports_metadata?