Problem: private classes self tests no longer ran
Problem: private classes self tests no longer ran

Solution: given the private classes symbols are intentionally not
exported, the self test functions cannot be called from the external
zyre_selftest binary.
Call them instead from the main class selftest function.

zeromq/zyre,zeromq/zyre,zeromq/zyre,zeromq/zyre,zeromq/zyre,zeromq/zyre,zeromq/zyre,zeromq/zyre