WCS scaling extension wrongly maps scale-factor to WCPS

[Piero Campalani]

WCS scaling extensions makes a wrong mapping to WCPS query in case of scale factors, turning lo and hi bounds to lo/factor and hi/factor bounds, but this breaks when lo or hi are 0 since the

service=WCS&
version=2.0.1&
request=GetCoverage&
coverageId=mr&
subset=i(0,7)&
subset=j(0,7)&
scalefactor=0.1

becomes:

select csv(scale( c[0:7,203:210], [0:70,2030:2100] )) from mr AS c

but the index extent then is scaled from 8 to 71 cells, while it should go to 80 cells.

[Piero Campalani]

See #788.