backend/indexing: Lower debug level when creating indexing tables
0 is too verbose
backend/indexing: Check input params for mysql_record_update() - aka update_fmid

Also add documentation for mysql_record_update()
backend/indexing: Verify that record has been actually updated by mysql_record_update()

mysql_record_update() should return MAPISTORE_ERR_NOT_FOUND if
there is no record for updated FMID/username pair
test/indexing: Add and refactor tests for indexing->update_fmid() interface
backend/indexing: mysql_record_del - add param checking and documentation

Also handle the case when input flags are not valid.
Kind of part of input parameters checking, but it is
implemented while executing the delete. The idea is not
to make input checking too bloated (especially if we have
more flags in future)
test/indexing: Prepopuldate indexing DB with existing FMDI/URI to test with
test/indexing: Refactor tests for indexing->del_fmid() interface
backend/indexing: mysql_record_get_uri() input param check and documentation
test/indexing: Refactor tests for indexing->get_uri() interface
backend/indexing: mysql_record_get_fmid() input check

also fixed the case when mapistore URI we search for does not
exists in DB - in this case, we should return MAPISTORE_ERR_NOT_FOUND
test/indexing: Refactor tests for indexing->get_fmid() interface