storage_support.cpp: add NULL check

check_path_name() had NULL check of path, but its result was not used.
So, add if statement to return B_BAD_VALUE when path is NULL.

Change-Id: I8ceec5d592267bf0f00f606eba44c0ecaef5a209
Reviewed-on: https://review.haiku-os.org/628
Reviewed-by: waddlesplash <[email protected]>

src/kits/storage/storage_support.cpp

@@ -383,7 +383,10 @@ check_entry_name(const char *entry)
 status_t
 check_path_name(const char *path)
 {
+	// check the path is not NULL
 	status_t error = (path ? B_OK : B_BAD_VALUE);
+	if (error == B_BAD_VALUE)
+		return error;
 	// check the path components
 	const char *remainder = path;
 	int32 length, nextComponent;