The target_dir config in reltool allows you to put your release in
a directory other than in ./NAME, so we should look in the parent
directory of that to find the new and old versions instead of
simply looking in ./
Move untaring and retaring into a temporary path instead of in ./
to prevent name collisions with "releases" and "lib" that might
exist already. Having a subdirectory rel/releases/ can be useful.
get_apps/3 now returns which apps have been added, removed and ugpgraded
in a reasonable way. It should prove more usable should we want to
access any of those lists in future appup related changes.
This commit changes how rebar determines which apps have been
updated, added and removed from a release during appup generation.
Rather than use app files it now determines this from the rel file
in each version of the release. In addition it fixes a bug reported
on the mailing list when generating appups when an application has
been added or removed from either release.
Replace rebar_util:get_cwd/0 by rebar_utils:get_cwd/0. Luckily the
misspelt module name doesn't seem to have caused any harm, since
rebar_app_utils:is_app_dir/0 and rebar_rel_utils:is_rel_dir/0 aren't
called (only their /1 counterparts).
