update: do not try to parse a layer that failed to fetch

If a layer's repository didn't fetch properly then we should not be
trying to parse it.

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>

TODO

@@ -2,8 +2,6 @@ TODO:
 
 Bugs
 * Duplication of first maintainer when editing to add a second?
-* meta-tizen gives PathError in initial info gathering step
- * If a layer has not yet been fetched and it can't be then it still tries to parse it and blows up when querying git revision
 * meta-debian seems to be prompting for github credentials during recipe parsing?
 * Remote patches in SRC_URI trigger errors
 * We're wasting time gathering layer info at the start for layers that have not changed

layerindex/update.py

@@ -327,6 +327,10 @@ def main():
                         collections.add((layerbranch.collection, layerbranch.version))
 
                 for layer in layerquery:
+                    if layer.vcs_url in failedrepos:
+                        logger.info("Skipping update of layer %s - fetch failed" % layer.name)
+                        continue
+
                     layerbranch = layer.get_layerbranch(branch)
                     branchname = branch
                     branchdesc = branch