Fix a use-after-free issue

In CBinaryStream, a member gets used after it has been destroyed. This was
caught by a static code analyser.

Issue: GMINL-1702
Change-Id: I5c93855f12a8f392e1f4249a15048816fb0f13ce
Signed-off-by: David Wagner <david.wagner@intel.com>
Reviewed-on: https://android.intel.com/278483
Reviewed-by: cactus <cactus@intel.com>
Tested-by: cactus <cactus@intel.com>
Reviewed-by: Beatty, Robert M <robert.m.beatty@intel.com>
Tested-by: Beatty, Robert M <robert.m.beatty@intel.com>
Merge pull request #17 from Makohoek/static_analysis_fix

Fix a use-after-free issue