[Ohrrpgce] SVN: teeemcee/11056 Fix switch_gfx crashing if called with invalid backend

[subversion at HamsterRepublic.com]

teeemcee
2019-03-23 01:03:38 -0700 (Sat, 23 Mar 2019)
192
Fix switch_gfx crashing if called with invalid backend

(This follows an earlier fix where switch_gfx was call with "sdl" when it should
have been called with "sdl2" when linked with gfx_sdl2)
---
U   wip/backends.bas
U   wip/common.rbas