Recognize + as a valid part of a phone number

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@2617 65c4cc65-6c06-0410-ace0-fbb531ad65f3

callerid.c

@@ -511,7 +511,7 @@ int ast_isphonenumber(char *n)
 	if (!n || !strlen(n))
 		return 0;
 	for (x=0;n[x];x++)
-		if (!strchr("0123456789*#", n[x]))
+		if (!strchr("0123456789*#+", n[x]))
 			return 0;
 	return 1;
 }