Fix some compiler warnings (miscellaneous)
https://bugs.webkit.org/show_bug.cgi?id=80790

Patch by Rob Buis <rbuis@rim.com> on 2013-04-15
Reviewed by Darin Adler.

It does not seem needed to initialize jpeg_create_compress struct to zero,
all that is needed is set the err field. See for instance SkImageDecoder_libjpeg.cpp.

* platform/image-encoders/JPEGImageEncoder.cpp:
(WebCore::compressRGBABigEndianToJPEG):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@148442 268f45cc-cd09-0410-ab3c-d52691b4dbfc