copies: delete now-unnecessary check for "a == b" before "a.descendant(b)"
Unnecessary since
879cbdde63df (revlog: do inclusive descendant
testing (API), 2018-06-21).
Differential Revision: https://phab.mercurial-scm.org/D3935
https://bz.mercurial-scm.org/1089
$ hg init
$ mkdir a
$ echo a > a/b
$ hg ci -Am m
adding a/b
$ hg rm a
removing a/b
$ hg ci -m m a
$ mkdir a b
$ echo a > a/b
$ hg ci -Am m
adding a/b
$ hg rm a
removing a/b
$ cd b
Relative delete:
$ hg ci -m m ../a
$ cd ..