Fixed a possible bug in path_to_vnode(): if called before a root

file system has been mounted, it would have crashed (that for example
happened if you deleted the kernel settings file...).


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@12547 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/system/kernel/fs/vfs.cpp

@@ -1449,6 +1449,11 @@ path_to_vnode(char *path, bool traverseLink, struct vnode **_vnode, bool kernel)
 
 	// figure out if we need to start at root or at cwd
 	if (*path == '/') {
+		if (sRoot == NULL) {
+			// we're a bit early, aren't we?
+			return B_ERROR;
+		}
+
 		while (*++path == '/')
 			;
 		start = sRoot;