Fix function require_splitter
Fix function require_splitter

The function returns whether a V4V6 splitter app is required.  Before it
checked whether an parameter `on-a-stick` was a command line argument,
but this should not be the case as an on-a-stick setup is also possible
when a configuration file has only one instance and one queue.

alexandergall/snabbswitch,snabbco/snabb,snabbco/snabb,Igalia/snabbswitch,Igalia/snabb,eugeneia/snabb,alexandergall/snabbswitch,eugeneia/snabb,alexandergall/snabbswitch,SnabbCo/snabbswitch,alexandergall/snabbswitch,Igalia/snabb,Igalia/snabb,Igalia/snabbswitch,alexandergall/snabbswitch,Igalia/snabb,snabbco/snabb,Igalia/snabbswitch,eugeneia/snabb,snabbco/snabb,Igalia/snabb,SnabbCo/snabbswitch,Igalia/snabbswitch,eugeneia/snabb,eugeneia/snabb,Igalia/snabb,snabbco/snabb,eugeneia/snabb,Igalia/snabb,alexandergall/snabbswitch,alexandergall/snabbswitch,SnabbCo/snabbswitch,Igalia/snabbswitch,snabbco/snabb,snabbco/snabb,snabbco/snabb,eugeneia/snabb,eugeneia/snabb,alexandergall/snabbswitch,SnabbCo/snabbswitch,Igalia/snabb