Fixed crash if initialization of EGL failed but was tried again later.

The internal function SDL_EGL_LoadLibrary() did not delete and remove a mostly
uninitialized data structure if loading the library first failed. A later try to
use EGL then skipped initialization and assumed it was previously successful
because the data structure now already existed. This led to at least one crash
in the internal function SDL_EGL_ChooseConfig() because a NULL pointer was
dereferenced to make a call to eglBindAPI().

BUGS.txt

@@ -0,0 +1,16 @@
+
+Bugs are now managed in the SDL bug tracker, here:
+
+    http://bugzilla.libsdl.org/
+
+You may report bugs there, and search to see if a given issue has already
+ been reported, discussed, and maybe even fixed.
+
+
+You may also find help on the SDL mailing list. Subscription information:
+
+    http://lists.libsdl.org/listinfo.cgi/sdl-libsdl.org
+
+Bug reports are welcome here, but we really appreciate if you use Bugzilla, as
+ bugs discussed on the mailing list may be forgotten or missed.
+