base-filesystem: skip fchownat() if the previous mkdirat() on same path failed (#5548)

If we are working on a path that was marked to be ignored on errors, and
the mkdirat() fails then add a continue statement and skip fchownat() call.
This avoids the case where UID/GID are valid and we run fchownat() on
non existent path which will fail hard even on paths that we want to
ignore in case of errors.

src/shared/base-filesystem.c

@@ -117,6 +117,8 @@ int base_filesystem_create(const char *root, uid_t uid, gid_t gid) {
 
                         if (!table[i].ignore_failure)
                                 return -errno;
+
+                        continue;
                 }
 
                 if (uid != UID_INVALID || gid != UID_INVALID) {