fix compiler warning - windows

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@15482 d0543943-73ff-0310-b7d9-9358b9ac24b2

src/include/switch_utils.h

@@ -321,7 +321,7 @@ static inline char *switch_sanitize_number(char *number)
 
 	while((q = strrchr(p, '@'))) *q = '\0';
  
-	for(i = 0; i < strlen(warp); i++) {
+	for(i = 0; i < (int)strlen(warp); i++) {
 		while(p && (q = strchr(p, warp[i]))) p = q + 1;
 	}