serveronly: fix reposetup
The local 'reposetup' function was shadowing the extension helper one. We add a
test for obshashrange using 'serveronly' since this is the item that made use
discover the issue.
#require test-repo pyflakes
Copied from Mercurial core (60ee2593a270)
$ cd "`dirname "$TESTDIR"`"
run pyflakes on all tracked files ending in .py or without a file ending
(skipping binary file random-seed)
$ hg locate 'set:(**.py or grep("^#!.*python")) - removed()' 2>/dev/null \
> | xargs pyflakes 2>/dev/null