hgweb: enable reading styles from resources in frozen binaries
All we need to do to read styles from resources is to pass the
file-like object we get from `open_template()` on to `frommapfile()`.
This takes the number of failing tests with PyOxidizer from 62 to 54.
Differential Revision: https://phab.mercurial-scm.org/D8901
fixbundle() {
grep -v 'saving bundle' | grep -v 'saved backup' | \
grep -v added | grep -v adding | \
grep -v "unable to find 'e' for patching" | \
grep -v "e: No such file or directory" | \
cat
}