vesa: fold framebuffer driver into vesa driver.

* The app_server isn't designed to support two fallback drivers, so
  on systems using UEFI to boot, the framebuffer driver will often
  win when other drivers would likely work on those systems.

build/jam/images/definitions/minimum

@@ -144,7 +144,7 @@ SYSTEM_NETWORK_PROTOCOLS =
 
 SYSTEM_ADD_ONS_ACCELERANTS = [ FFilterByBuildFeatures
 	x86,x86_64 @{
-		framebuffer.accelerant vesa.accelerant
+		vesa.accelerant
 	}@ # x86,x86_64
 ] ;
 
@@ -172,7 +172,7 @@ SYSTEM_ADD_ONS_DRIVERS_AUDIO_OLD = ;
 
 SYSTEM_ADD_ONS_DRIVERS_GRAPHICS = [ FFilterByBuildFeatures
 	x86,x86_64 @{
-		framebuffer vesa
+		vesa
 	}@ # x86,x86_64
 ] ;