Avoid cppcheck warnings; removing unused vars and a bit of cleanup.

Patch by: junky
Review: https://reviewboard.asterisk.org/r/1743/


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@362307 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

@@ -4509,7 +4509,7 @@ static int sip_sendtext(struct ast_channel *ast, const char *text)
 	}
 	if(!is_method_allowed(&dialog->allowed_methods, SIP_MESSAGE)) {
 		ast_debug(2, "Trying to send MESSAGE to device that does not support it.\n");
-		return(0);
+		return 0;
 	}
 
 	debug = sip_debug_test_pvt(dialog);