Fixed gray value stretching issue in case of rotated ENVI images without inherent nodata value.

Signed-off-by: Daniel Scheffler <danschef@gfz-potsdam.de>
3 jobs for bugfix/fix_stretching in 1 minute and 23 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Test
passed #10743
test_geoarray

00:00:49

70.0%
passed #10744
test_styles

00:00:19

 
  Cleanup
passed #10745
cleanup_pypirc

00:00:14