Clarify license terms for Romain Guy's artwork.

As discussed with Romain Guy in the email thread, the Apache 2.0
license applies to the affected .jpg files now and retroactively from
the time of import.

The exiftool did not remove the old CreativeCommons metadata.

The images were altered using the bless hex editor to manually
overwrite the metadata.

$ exiftool -URL -WebStatement -UsageTerms tests/CanvasCompare/res/drawable/sunset1.jpg
URL                             : http://www.apache.org/licenses/LICENSE-2.0
Web Statement                   : http://www.apache.org/licenses/LICENSE-2.0
Usage Terms                     : Apache License Version 2.0

$ exiftool -URL -WebStatement -UsageTerms tests/HwAccelerationTest/res/drawable-hdpi/sunset1.jpg
URL                             : http://www.apache.org/licenses/LICENSE-2.0
Web Statement                   : http://www.apache.org/licenses/LICENSE-2.0
Usage Terms                     : Apache License Version 2.0

$ exiftool -URL -WebStatement -UsageTerms tests/HwAccelerationTest/res/drawable/sunset1.jpg
URL                             : http://www.apache.org/licenses/LICENSE-2.0
Web Statement                   : http://www.apache.org/licenses/LICENSE-2.0
Usage Terms                     : Apache License Version 2.0

Change-Id: Icbd8c8c65ca521751d63a213377e3ababff0b7da