Fix uninitialized color filter data on GrPaint

[bsalomon, 2012-08-16 15:01:19]

Found by valgrind. Once we get to fixing/replacing GrPaint it should be easier
to prevent these errors. GrPaint's fColorFilterColor wasn't initialized when
there was a color filter that was either a color matrix or color table. This
gets copied to GrDrawState and could cause the in order buffer to unnecessarily
insert a new draw state.

[TomH, 2012-08-16 15:02:52]

LGTM

[bsalomon, 2012-08-16 15:07:17]

Closed with r5125.