dir.c: rename path_excluded() to is_path_excluded()

Start adopting clearer names for exclude functions.  This 'is_*'
naming pattern for functions returning booleans was agreed here:

http://thread.gmane.org/gmane.comp.version-control.git/204661/focus=204924Signed-off-by: NAdam Spiers <git@adamspiers.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

builtin/add.c

@@ -453,7 +453,7 @@ int cmd_add(int argc, const char **argv, const char *prefix)
 			    && !file_exists(pathspec[i])) {
 				if (ignore_missing) {
 					int dtype = DT_UNKNOWN;
-					if (path_excluded(&check, pathspec[i], -1, &dtype))
+					if (is_path_excluded(&check, pathspec[i], -1, &dtype))
 						dir_add_ignored(&dir, pathspec[i], strlen(pathspec[i]));
 				} else
 					die(_("pathspec '%s' did not match any files"),

builtin/ls-files.c

@@ -203,7 +203,7 @@ static void show_ru_info(void)
 static int ce_excluded(struct path_exclude_check *check, struct cache_entry *ce)
 {
 	int dtype = ce_to_dtype(ce);
-	return path_excluded(check, ce->name, ce_namelen(ce), &dtype);
+	return is_path_excluded(check, ce->name, ce_namelen(ce), &dtype);
 }
 
 static void show_files(struct dir_struct *dir)

dir.c

@@ -685,7 +685,7 @@ void path_exclude_check_clear(struct path_exclude_check *check)
  * A path to a directory known to be excluded is left in check->path to
  * optimize for repeated checks for files in the same excluded directory.
  */
-int path_excluded(struct path_exclude_check *check,
+int is_path_excluded(struct path_exclude_check *check,
 		     const char *name, int namelen, int *dtype)
 {
 	int i;

dir.h

@@ -123,7 +123,7 @@ struct path_exclude_check {
 };
 extern void path_exclude_check_init(struct path_exclude_check *, struct dir_struct *);
 extern void path_exclude_check_clear(struct path_exclude_check *);
-extern int path_excluded(struct path_exclude_check *, const char *, int namelen, int *dtype);
+extern int is_path_excluded(struct path_exclude_check *, const char *, int namelen, int *dtype);
 
 
 extern int add_excludes_from_file_to_list(const char *fname, const char *base, int baselen,

unpack-trees.c

@@ -1372,7 +1372,7 @@ static int check_ok_to_remove(const char *name, int len, int dtype,
 		return 0;
 
 	if (o->dir &&
-	    path_excluded(o->path_exclude_check, name, -1, &dtype))
+	    is_path_excluded(o->path_exclude_check, name, -1, &dtype))
 		/*
 		 * ce->name is explicitly excluded, so it is Ok to
 		 * overwrite it.