fix systemd unit

distrib/systemd/oragono.service

@@ -2,8 +2,9 @@
 Description=oragono
 After=network.target
 # If you are using MySQL for history storage, comment out the above line
-# and uncomment these two instead:
-# Requires=mysql.service
+# and uncomment these two instead (you must independently install and configure
+# MySQL for your system):
+# Wants=mysql.service
 # After=network.target mysql.service
 
 [Service]