Fix memory leak in CMS

Quoting iccjpeg.h:
  * IMPORTANT: the data at **icc_data_ptr has been allocated with malloc()
  * and must be freed by the caller with free() when the caller no longer
  * needs it.  (Alternatively, we could write this routine to use the
  * IJG library's memory allocator, so that the data would be freed implicitly
  * at jpeg_finish_decompress() time.  But it seems likely that many apps
  * will prefer to have the data stick around after decompression finishes.)

Reviewed By: ngraham

Differential Revision: https://phabricator.kde.org/D28344