dirstatemap: move `_drop_entry` out of the common methods
Only the Python implementation uses it.
Differential Revision: https://phab.mercurial-scm.org/D12514
#!/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)