HR fix for issue #186587

 >Description of the bug (including IZ #)
#186587: NPE at ElCompletionProvider.isAfterElDelimiter()

 >Impact assessment i.e. why it is a showstopper?
It was only reproduced once (by Petr Pis) but it caused a nasty loop of 
exceptions during basic JSP editing.

 > Risk assessment i.e. why is it safe?
The fix is a trivial NPE check.

 > Confirmation of peer code review and QE verification of fix
The fix was discussed with Vita Stejskal, QE verification may be tricky 
as the issue is not reproducible

 > Changeset info (for reviewing diffs)
http://hg.netbeans.org/web-main/rev/1fe417dc3a0d

-TS