[PATCH 3 of 3 various] branchcache: stay silent if failing to read cache files

[Mads Kiilerich]

# HG changeset patch
# User Mads Kiilerich <madski at unity3d.com>
# Date 1421194526 -3600
#      Wed Jan 14 01:15:26 2015 +0100
# Node ID 7870d376ee8f4c15b412912600a4e295f1b3fb9b
# Parent  31a330fcad90837e0c0d858db69e67a7f74ec997
branchcache: stay silent if failing to read cache files

The warning has in some cases incorrectly attributed unrelated problems to rbc.

Instead, just do like the branch head cache does and stay quiet when reading
fails. The cache will be missing the first time a repo is used. It is a normal
situation and there is no reason to make a note of that.

diff --git a/mercurial/branchmap.py b/mercurial/branchmap.py
--- a/mercurial/branchmap.py
+++ b/mercurial/branchmap.py
@@ -335,8 +335,6 @@ class revbranchcache(object):
             self._rbcsnameslen = len(bndata) # for verification before writing
             self._names = [encoding.tolocal(bn) for bn in bndata.split('\0')]
         except (IOError, OSError), inst:
-            repo.ui.debug("couldn't read revision branch cache names: %s\n" %
-                          inst)
             if readonly:
                 # don't try to use cache - fall back to the slow path
                 self.branchinfo = self._branchinfo
diff --git a/tests/test-casefolding.t b/tests/test-casefolding.t
--- a/tests/test-casefolding.t
+++ b/tests/test-casefolding.t
@@ -28,7 +28,6 @@ test case collision on rename (issue750)
   a
   committing manifest
   committing changelog
-  couldn't read revision branch cache names: * (glob)
   committed changeset 0:07f4944404050f47db2e5c5071e0e84e7a27bba9
 
 Case-changing renames should work:
diff --git a/tests/test-convert-svn-encoding.t b/tests/test-convert-svn-encoding.t
--- a/tests/test-convert-svn-encoding.t
+++ b/tests/test-convert-svn-encoding.t
@@ -53,7 +53,6 @@ Convert while testing all possible outpu
   source: svn:afeb9c47-92ff-4c0c-9f72-e1f6eb8ac9af/trunk at 1
   converting: 0/6 revisions (0.00%)
   committing changelog
-  couldn't read revision branch cache names: * (glob)
   4 hello
   source: svn:afeb9c47-92ff-4c0c-9f72-e1f6eb8ac9af/trunk at 2
   converting: 1/6 revisions (16.67%)