samples: net: civetweb: Ignore return values

We do not need the return values from various calls to pthread_*()
functions.

Coverity-CID: 203462
Coverity-CID: 203535

Fixes #18376
Fixes #18377

Signed-off-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
1 file changed