Fix perl use of 'use lib'

The 'use lib' logic happens in the pre-compile stage, so one cannot
use normal 'if' logic to use a particular INC.  Instead, just make sure
that best dir is added to 'use lib' last since it prepends to INC.

lf_firemod.pl

@@ -15,12 +15,12 @@ $SIG{ __WARN__ } = sub { Carp::confess( @_ ) };
 
 # Un-buffer output
 $| = 1;
-if (-f "LANforge/Endpoint.pm" ) {
-   use lib "./";
-}
-else {
-  use lib '/home/lanforge/scripts';
-}
+
+# use lib prepends to @INC, so put lower priority first
+# This is before run-time, so cannot condition this with normal 'if' logic.
+use lib '/home/lanforge/scripts';
+use lib "./";
+
 use LANforge::Endpoint;
 use LANforge::Port;
 use LANforge::Utils;