Problem: #594 missed README.md, when renamed zyre_set_ephemeral_port().
Problem: #594 missed README.md, when renamed zyre_set_ephemeral_port().

Solution: Update README.md, accordingly (issue #595).

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