shared/frame: fix potential memory leak in frame_create

In frame_create, we need to destroy any frame buttons created
in preceding calls to frame_button_create during the function
execution if any of the successive calls to frame_button_create
fail.

This has minimal severity since most, if not all, cases in
frame_button_create that result in a fail (i.e. NULL result) means
a program is OOM and the program will have to exit/abort anyway.

Signed-off-by: U. Artie Eoff <ullysses.a.eoff@intel.com>