Original commit added incorrect config section [heat_clients]
which should actually be [clients_heat].
Also adds workaround for bug 1750395 which affects creation
of server without specifying network (>= rocky). This is needed
for amulet tests to pass.
Change-Id: I8f1036bd8797a336d836a6b3f6fa9cb50f7a8fa8
Closes-Bug: #1770144
582e352144