egl: don't fill client apis string forever.

We never reset the string on eglTerminate, so it grows
for ever on multiple eglInitialise.

Reviewed-by: Brian Paul <brianp@vmware.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

src/egl/main/eglapi.c

@@ -514,6 +514,7 @@ eglTerminate(EGLDisplay dpy)
 
       drv->API.Terminate(drv, disp);
       /* do not reset disp->Driver */
+      disp->ClientAPIsString[0] = 0;
       disp->Initialized = EGL_FALSE;
    }