New Defects reported by Coverity Scan for LibreOffice

[Caolán McNamara]

cid#1352479 and cid#1352479 point out
that 54e3ea8a86a309990f5edf78948bfe18dd2de96b "tdf#97715 fix inv. scale
calculation in DrawTransformedTexture" means that the calculations to
derive ixscale and iyscale are done with integers not floats so the
result is always an integer. 

Is that intentional ?, if it is then the ixscale could be changed to be
integers and then I suppose fastAreaScaling = ( ixscale == int( ixscale
) && iyscale == int( iyscale )) becomes always true.

C.