scanner: don't error on partially used globs
scanner: don't error on partially used globs

This meant that using something like `scanignore=*` would error if there were
ignores happening in some directories/files, but not all.

Fixes #110

f-droid/fdroidserver,f-droid/fdroidserver,f-droid/fdroid-server,fdroidtravis/fdroidserver,f-droid/fdroidserver,fdroidtravis/fdroidserver,f-droid/fdroid-server,f-droid/fdroidserver,f-droid/fdroid-server,fdroidtravis/fdroidserver,f-droid/fdroid-server,f-droid/fdroidserver,f-droid/fdroid-server,fdroidtravis/fdroidserver