test: account for discovery log page entry stripping

test: account for discovery log page entry stripping

The discovery log page tests incorrectly assumed the log page
nvmf_get_discovery_log() returns exactly matches what was fetched.
This failed to account for the trailing space trimming
of the TRSVCID and TRADDR fields.
If the arbitrary entries happened to contain trailing spaces
for these fields, the test cases would fail.
Generate arbitrary entries with space-padded strings for the log page
and corresponding expected entries with NUL-padded strings.

Signed-off-by: Caleb Sander <csander@purestorage.com>