Add the ability to check the permissions and type of a file within the
framework of pactest. Two new rules can be used:
self.addrule("FILE_TYPE=bin/foo|file")
self.addrule("FILE_MODE=bin/bar|644")
TODO: add the ability to add different types of files (eg links) via the test
package building framework, and add the ability to change the modes on files.
Signed-off-by: Dan McGee <dan@archlinux.org>