Set the options of an authorized key comma separated

According to the sshd man page, no spaces are permitted between the
options of an authorized ssh key

library/system/authorized_key

@@ -245,11 +245,15 @@ def writekeys(module, filename, keys):
                 (keyhash,type,options,comment) = key
                 option_str = ""
                 if options:
+                    option_strings = []
                     for option_key in options.keys():
                         if options[option_key]:
-                            option_str += "%s=%s " % (option_key, options[option_key])
+                            option_strings.append("%s=%s" % (option_key, options[option_key]))
                         else:
-                            option_str += "%s " % option_key
+                            option_strings.append("%s " % option_key)
+
+                    option_str = ",".join(option_strings)
+                    option_str += " "
                 key_line = "%s%s %s %s\n" % (option_str, type, keyhash, comment)
             except:
                 key_line = key