When a module adds a command to a named service, depend on the module
that adds that service. Otherwise, service_named_bind_command() just
does nothing if the service doesn't exist, so make sure it exists
first.

Likewise, the dependency and conflict macros return from mod_init()
without doing any cleanup. The mod_deinit() function does not get
called if mod_init() fails -- so mod_init() needs to do any cleanup
should it fail. This means these macros need to be first.

Finally, these macros expand to an if() block, so they don't need a
semicolon on the end; they are not function calls or do-while loops.