Remove unused variable in config schema.

Author: prat0088

lib/Serge/Sync/Plugin/VCS/p4.pm

@@ -35,7 +35,6 @@ sub init {
 
     $self->merge_schema({
         p4_cmd             => 'STRING',
-        p4_config          => 'STRING',
         client_name        => 'STRING',
         client_owner       => 'STRING',
         client_description => 'STRING',