when they contain the '!' operator.
Added an implementation for the method Item_func_not::print. 
The method encloses any NOT expression into extra parentheses to avoid
incorrect stored representations of views that use the '!' operators.
Without this change when a view was created that contained
the expression !0*5  its stored representation contained not this
expression but rather the expression not(0)*5 . 
The operator '!' is of a higher precedence than '*', while NOT is 
of a lower precedence than '*'. That's why the expression !0*5 
is interpreted as not(0)*5, while the expression not(0)*5 is interpreted
as not((0)*5) unless sql_mode is set to HIGH_NOT_PRECEDENCE.
Now we translate !0*5 into (not(0))*5.