RTF import: fix handling of font color from paragraph style

Conflicts:
	sw/qa/extras/rtfimport/rtfimport.cxx

Change-Id: I6bbad2d69863020ea870be800f49e13e763b80bf
Reviewed-on: https://gerrit.libreoffice.org/7667
Reviewed-by: Andras Timar <andras.timar@collabora.com>
Tested-by: Andras Timar <andras.timar@collabora.com>