Avoid crash when unbinding wallpaper

A wallpaper service might have crashed before we try
to unbind it, in this case a runtime exception will
be thrown. Let's just ignore it since there is nothing
else to be done.

Bug: 62828614
Test: manually set Windy wallpaper and resize it
Change-Id: If9882ea27aaf3c92d2069ae6c8ef409c6ae2fa91
(cherry picked from commit b989a5e9de2d0300c578e79705f670c2b7ffe199)
1 file changed