Quick ansible-doc fix -- don't run pager if there was an error (no text)

lib/ansible/cli/doc.py

@@ -137,7 +137,8 @@ class DocCLI(CLI):
                 display.vvv(traceback.print_exc())
                 raise AnsibleError("module %s missing documentation (or could not parse documentation): %s\n" % (module, str(e)))
 
-        self.pager(text)
+        if text:
+            self.pager(text)
         return 0
 
     def find_modules(self, path):