log: do not use exact matcher for --patch --follow without file (
issue4319)
e2530d4a47c1 is valid only if file argument is specified. If no pattern
specified, it can simply fall back to the original matcher.
$ hg init
$ echo This is file a1 > a
$ hg add a
$ hg commit -m "commit #0"
$ ls
a
$ echo This is file b1 > b
$ hg add b
$ hg commit -m "commit #1"
$ hg co 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
B should disappear
$ ls
a