bundle2: fix broken compression engine assertion
bundletype() is a function, so it needs to be called, and it is
documented to return a 2-tuple. This code is untested, so that's why
we haven't noticed the bad assertion.
Differential Revision: https://phab.mercurial-scm.org/D5155
#require test-repo jshint hg10
$ . "$TESTDIR/helpers-testrepo.sh"
run jshint on all tracked files ending in .js except vendored dependencies
$ cd "`dirname "$TESTDIR"`"
$ testrepohg locate 'set:**.js' \
> 2>/dev/null \
> | xargs jshint