branchcache: store filtered hash and obsolete hash independently for V3
This will avoid the bug covered in tests/test-branches-obsolete.t when we stop
storing all heads explicitly in V3.
#!/usr/bin/env python3
import errno
import os
import sys
for f in sys.argv[1:]:
try:
print(f, '->', os.readlink(f))
except OSError as err:
if err.errno != errno.EINVAL:
raise
print(f, '->', f, 'not a symlink')
sys.exit(0)