vircapstest: Properly report error for failed tests

vircapstest: Properly report error for failed tests

There are two macros used in the test: CAPSCOMP and CAPS_EXPECT_ERR.
Both run a test case and if a failure occurred, they set the @ret
variable to a value of -1 to indicate an error. Well, that's what they
should do. Due to a typo, they set the variable to a positive one
effectively masking any failed test.

Then, we have couple of tests failing. Fix them too.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>