JunitTest_chart_unoapi fails here with "assert(!hasCurrent())" because
the initialization apparently fails due to lack of a
wglCreateContextAttribsARB in the VM, so ensure that the hTempRC is not
active and also deleted in all cases.

(cherry picked from commit 5efad739)

vcl: even in the newfangled OpenGL world, initializing members is ...
... still a good idea.
(cherry picked from commit 37d24365)

Change-Id: I7e03b95d1146af48a24e34692c3c2827298fccee
Reviewed-on: https://gerrit.libreoffice.org/19040Reviewed-by: Markus Mohrhard <markus.mohrhard@googlemail.com>
Tested-by: Markus Mohrhard <markus.mohrhard@googlemail.com>
(cherry picked from commit 418d7171)