Change OF min version to 3.9.4

Since OF 3.9.3 has a bug whereby it thinks 3.10.0 is older than 3.9.3,
this causes a problem as OF 3.9.3 will attempt to install plugins that
it can not run.  This change puts the 3.10.0 plugins at a release that
will not happen, which keeps them affectively from getting installed.