test: verify that we can open R/O files

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
test: switch to the "nobody" user so file read/only vs read/write checks work

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
test: if we fail to setuid, emit a warning and continue

Unfortunately we can't seem to setuid(nobody) on travis.

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Merge pull request #16 from djs55/relative-paths

Add test for opening files read/only