tests/test-1102

util: stop overwriting sha1, overwrite _fastsha1 instead

Some modules (like revlog) would import util.sha1 as _sha1. This
defeats the purpose of having util.sha1 overwrite itself with a faster
version -- revlog would end up always calling the slow version. By
always delegating to util._fastsha1 we avoid this at the cost of an
extra (but unconditional) indirection.

#!/bin/sh

rm -rf a
hg init a
cd a
echo a > a
hg ci -Am0
hg tag t1 # 1
hg tag --remove t1 # 2

hg co 1
hg tag -r0 t1
hg tags