When 'Scalehint Units per Pixel' is configured for the WMS, Compute the scale hint with a pixel size of 0.28mm x 0.28mm.
Otherwise use the min/max denominator as schalehint.
Reverted change: For wms 1.3.0 always use the scaledenominators and don't compute the units per pixel(0.28mm * 0.28mm).
wms 1.1.1 scalehint != 1.3.0 scaledenominators.