If key is not set in the cursor for search_near operation, only in case of lsm cursor returns error, all other cursor types will not return error.

As part of this, need to fix test_prepare03.py as well.

test_prepare03.py ( special handling for lsm cursor type)

if self.uri == 'lsm'
cursor.set_key(self.genkey(10))

No special handling should be required based on cursor type.