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.
Edited by Zwip-Zwap Zapony