Merge VideoBootStrap::available into VideoBootStrap::create

The two are only ever called together, and combining them makes it possible
to eliminate redundant symbol loading and redundant attempts to connect
to a display server.

src/video/haiku/SDL_bvideo.cc

@@ -124,7 +124,7 @@ HAIKU_CreateDevice(int devindex)
 
 VideoBootStrap HAIKU_bootstrap = {
     "haiku", "Haiku graphics",
-    HAIKU_Available, HAIKU_CreateDevice
+    HAIKU_CreateDevice
 };
 
 void HAIKU_DeleteDevice(SDL_VideoDevice * device)
@@ -185,11 +185,6 @@ int HAIKU_VideoInit(_THIS)
     return (0);
 }
 
-int HAIKU_Available(void)
-{
-    return (1);
-}
-
 void HAIKU_VideoQuit(_THIS)
 {
 

src/video/haiku/SDL_bvideo.h

@@ -33,7 +33,6 @@ extern "C" {
 extern void HAIKU_VideoQuit(_THIS);
 extern int HAIKU_VideoInit(_THIS);
 extern void HAIKU_DeleteDevice(_THIS);
-extern int HAIKU_Available(void);
 
 #ifdef __cplusplus
 }