EMPTY RESULT
Bug#14096685 WITHIN() YIELDS NO RESULTS WHEN
             SPATIAL INDEX IS USED

The ST_Contains & Within() functions doesn't
show correct result when executed with spatial
index.

The reason behind this problem is that the spatial
index for Contains and Within class of functions in
MyISAM is implemented in opposite order.

Fixed by adjusting the flag that controls which
implementation to use and item's rev_functype()
for Contains & Within functions.