Insufficient memory for terminating null of string in _XcursorThemeInherits

Fix does one byte of memory allocation for null termination of string.
https://bugs.freedesktop.org/show_bug.cgi?id=90857



Reviewed-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>