largefiles: rearrange how lfconvert detects non-local repos
Mainly this is so we can test that code; it has the side benefit of not
requiring network I/O to reject non-local repo URLs.
hg debuginstall
$ hg debuginstall
Checking encoding (ascii)...
Checking installed modules (*/mercurial)... (glob)
Checking templates (*/mercurial/templates)... (glob)
Checking commit editor...
Checking username...
No problems detected
hg debuginstall with no username
$ HGUSER= hg debuginstall
Checking encoding (ascii)...
Checking installed modules (*/mercurial)... (glob)
Checking templates (*/mercurial/templates)... (glob)
Checking commit editor...
Checking username...
no username supplied (see "hg help config")
(specify a username in your configuration file)
1 problems detected, please check your install!
[1]