Change RGB "FFFF00" -> "ffff00" to keep roundtrip test happy

Change-Id: I14e48d56b6f34be31a1580d448352b925f9aadde
Monkey see, monkey do?

At least, it makes CppunitTest_sw_ooxmlsdrexport succeed again.

Change-Id: I05b9de5366b0e3d2007311d00991758b6d6f8dba
Revert "sw: disable failing checks"

This reverts commit e7646e7e389a6a8c6481bd75127207b5090b126d.