Yum API is faster than calling out to repoquery. Looking through the commit logs it looks like we weren't previously doing that because of commit 14479e6adc

The message there is that Yum API prints an error message if the
rhn-plugin is in use and no rhn-certificate is available.  So instead of
using repoquery in preference always here we use repoquery in preference
if the rhn-plugin is enabled.

lib/ansible/modules/packaging/os/yum.py

@@ -154,12 +154,6 @@ EXAMPLES = '''
 
 def_qf = "%{name}-%{version}-%{release}.%{arch}"
 
-repoquery='/usr/bin/repoquery'
-if not os.path.exists(repoquery):
-    repoquery = None
-
-yumbin='/usr/bin/yum'
-
 def log(msg):
     syslog.openlog('ansible-yum', 0, syslog.LOG_USER)
     syslog.syslog(syslog.LOG_NOTICE, msg)
@@ -187,10 +181,6 @@ def install_yum_utils(module):
         yum_path = module.get_bin_path('yum')
         if yum_path:
             rc, so, se = module.run_command('%s -y install yum-utils' % yum_path) 
-            if rc == 0:
-                this_path = module.get_bin_path('repoquery')
-                global repoquery
-                repoquery = this_path
 
 def po_to_nevra(po):
 
@@ -475,10 +465,10 @@ def repolist(module, repoq, qf="%{repoid}"):
         ret = set([ p for p in out.split('\n') if p.strip() ])
     return ret
 
-def list_stuff(module, conf_file, stuff):
+def list_stuff(module, repoquerybin, conf_file, stuff):
 
     qf = "%{name}|%{epoch}|%{version}|%{release}|%{arch}|%{repoid}"
-    repoq = [repoquery, '--show-duplicates', '--plugins', '--quiet']
+    repoq = [repoquerybin, '--show-duplicates', '--plugins', '--quiet']
     if conf_file and os.path.exists(conf_file):
         repoq += ['-c', conf_file]
 
@@ -789,13 +779,24 @@ def latest(module, items, repoq, yum_basecmd, conf_file, en_repos, dis_repos):
 def ensure(module, state, pkgs, conf_file, enablerepo, disablerepo,
            disable_gpg_check, exclude):
 
+    yumbin = module.get_bin_path('yum')
     # need debug level 2 to get 'Nothing to do' for groupinstall.
     yum_basecmd = [yumbin, '-d', '2', '-y']
 
-    if not repoquery:
-        repoq = None
-    else:
-        repoq = [repoquery, '--show-duplicates', '--plugins', '--quiet']
+    # If rhn-plugin is installed and no rhn-certificate is available on the
+    # system then users will see an error message using the yum API.  Use
+    # repoquery in those cases.
+
+    my = yum_base(conf_file)
+    # A sideeffect of accessing conf is that the configuration is
+    # loaded and plugins are discovered
+    my.conf
+
+    repoq = None
+    if 'rhnplugin' in my.plugins._plugins:
+        repoquery = module.get_bin_path('repoquery', required=False)
+        if repoquery:
+            repoq = [repoquery, '--show-duplicates', '--plugins', '--quiet']
 
     if conf_file and os.path.exists(conf_file):
         yum_basecmd += ['-c', conf_file]
@@ -892,10 +893,11 @@ def main():
     if params['install_repoquery'] and not repoquery and not module.check_mode:
         install_yum_utils(module)
 
+    repoquerybin = module.get_bin_path('repoquery', required=False)
     if params['list']:
-        if not repoquery:
+        if not repoquerybin:
             module.fail_json(msg="repoquery is required to use list= with this module. Please install the yum-utils package.")
-        results = dict(results=list_stuff(module, params['conf_file'], params['list']))
+        results = dict(results=list_stuff(module, repoquerybin, params['conf_file'], params['list']))
         module.exit_json(**results)
 
     else: