openbsd: fix hostname setting

openbsd/_openbsdcontext.py

@@ -104,7 +104,7 @@ class Context(BaseContext):
     @staticmethod
     def set_hostname(hostname):
         with open('/etc/myname', 'w') as f:
-            f.write(hostname)
+            f.write(hostname + '\n')
 
         with open('/etc/hosts', 'w') as f:
             f.write("127.0.0.1 localhost\n"