Convert all incoming protocol numbers to string

PostgreSQL is more sensitive for types than MySQL when it selects
something from columns in database. So it fails when it tries to
select from string field comparing with integer value.

Added unit test to verify conversion of protocol numbers to
strings.

Closes-bug:#1381379

Change-Id: I0a29595403a07c66888871088d5549705a097f68
Merge "Convert all incoming protocol numbers to string"