typelib/registry: don't return possible null-reference

kudos to scan-build

Signed-off-by: Martin Zenzes <martin.zenzes@dfki.de>
various: fix "unused variable" warnings

low hanging fruits...

Signed-off-by: Martin Zenzes <martin.zenzes@dfki.de>
Merge pull request #5 from jmachowinski/fixes-through-scan-build

Fixes through scan build