package.bbclass: fix globbing for mask-like files

package.bbclass: fix globbing for mask-like files

When a package contains two files like "name*" and "name*smth" OE can't
properly package those, looping infinetely trying to build file list. The
reason is that first file name globs to two files and OE adds them both
into the list, then globs the first one again and gets two same files, etc.

Fix that.

Signed-off-by: Koen Kooi <koen@openembedded.org>