localrepo: move storevfs calculation out of if statement
In next patch, we will need this variable in else statement too. So, let's take
it out.
Differential Revision: https://phab.mercurial-scm.org/D9681
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 ..