WL#5802: Copy error codes from 5.6 to 5.5

This is a step towards making replication a library, such that the 5.6 rpl-lib 
can be plugged into the 5.5 core [WL#5675].

In 5.6, replication uses some error codes that currently do not exist in 5.5. The 
error messages are defined in core. In order to link the 5.6 rpl-lib to the 5.5 
core, the 5.5 core has to include all errors that exist in 5.6.

In this worklog, we backport all error messages from 5.6 to 5.5.