narrow: check for servers' narrow support before doing anything (BC)
Recently we introduced narrow capabilities for the server. So we can check
whether a server has narrow clone support or not before doing anything. This is
BC because new clients won't be able to extend from old narrow-enabled servers.
I *think* narrow is not used much (maybe just inside Google), also it's
experimental so I think we can change this. We will need to this someday anyway.
The "doesn't" in error is changed to "does not" because I think that's we do in
core. I also changed one more instance of the error message to use 'does not'
for consistency.
Differential Revision: https://phab.mercurial-scm.org/D4789
$ 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