revlog: add punched revision flag
index flag to identify a revision as punched, i.e. it contains no data.
REVIDX_PUNCHED_FLAG = 2, is used to mark a revision as punched.
REVIDX_KNOWN_FLAGS is the accumulation of all index flags.
#!/bin/sh
hg init a
cd a
mkdir a
echo a > a/b
hg ci -Am m
hg rm a
hg ci -m m a
mkdir a b
echo a > a/b
hg ci -Am m
hg rm a
cd b
# relative delete
hg ci -m m ../a