Copy libjpeg.gyp from third_party/externals/libjpeg/ to gyp/

This should get our use of libjpeg-from-source unblocked; see http://code.google.com/p/skia/issues/detail?id=543 ('wrap libjpeg.gyp from Chrome's libjpeg port, rather than making our own copy') for a better long-term solution.
Review URL: https://codereview.appspot.com/5908058

git-svn-id: http://skia.googlecode.com/svn/trunk@3496 2bbb7eff-a529-9590-31e7-b0007b416f81
2 files changed