Fix OpenGL V_DrawCroppedPatch (Fixes #452)

This merge request undoes !1297 (merged) (which caused #452 (closed)), and fixes the problem that it tried to fix more appropriately.

It also fixes OpenGL V_DrawCroppedPatch blacking out the screen when a 320x200 patch is used; software V_DrawCroppedPatch already doesn't do that, since the patch is supposed to be cropped, not screen-filling.

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changed the description

added Regression label

added OpenGL renderer label

changed milestone to %2.2.9

merged

mentioned in commit 91187f91