tests/test-permissions

Added ability to clone from a local repository to a (new) remote one.

Rearranged the clone command a good bit to make sure it validates that
the source does exist and that the destination doesn't before doing anything.
Before I moved the source repo check it would create the destination
repository before it verified the source existed.

Moved the responsibility for creating the destination repo root directory
entirly into the localrepo class so that local to local cloning doesn't break.
This also simplifies the code a bit since it's no longer being done in both
clone and init.

Changed the names of the 'repo' and 'other' variables to 'dest_repo' and
'src_repo' to maintain my sanity.

Passes 82/83 tests. The only failure is the version number test, which I
suspect is supposed to fail since it comes from a generated file.

#!/bin/sh

hg init
echo foo > a
hg add a
hg commit -m "1" -d "1000000 0"
hg verify
chmod -r .hg/data/a.i
hg verify 2>/dev/null || echo verify failed
chmod +r .hg/data/a.i
hg verify 2>/dev/null || echo verify failed
chmod -w .hg/data/a.i
echo barber > a
hg commit -m "2" -d "1000000 0" 2>/dev/null || echo commit failed