qdoc: Simplification of target ref construction

qdoc: Simplification of target ref construction

This change is being done to simplify qdoc,
but the motivation was to fix a segfault in
qdoc when running the release version of
qdoc on linux. The change improves qdoc by
simplifying the code whether it fixes the
segfault or not.

Change-Id: I2c865f7f1e2a44763aa7349d1bd739ad562f4029
Reviewed-by: Jerome Pasion <jerome.pasion@digia.com>