Only destroy huffman if build succeeded.

Only destroy huffman if build succeeded.

The earlier code assumed that if jpeg_create_huffman_index
succeeded but jpeg_build_huffman_index failed that the
index would still need to be destroyed. This is not the
case. Only call jpeg_destroy_huffman_index if both
succeeded.

BUG=http://b.corp.google.com/issue?id=10263847

Committed: https://code.google.com/p/skia/source/detail?r=10954

[scroggo, 2013-08-21 23:50:21]

I've also submitted this CL to android repo for review.

[scroggo, 2013-08-27 20:42:29]

Committed patchset #1 manually as r10954 (presubmit successful).