fix(backend): spinoff_volumes is now spinoff

lib/Ravada/Front/Domain.pm

@@ -176,7 +176,7 @@ sub set_max_mem         { confess "TODO" }
 sub set_memory          { confess "TODO" }
 sub shutdown            { confess "TODO" }
 sub shutdown_now        { confess "TODO" }
-sub spinoff_volumes     { confess "TODO" }
+sub spinoff             { confess "TODO" }
 sub start               { confess "TODO" }
 
 sub dettach             { confess "TODO" }

lib/Ravada/VM.pm

@@ -500,7 +500,7 @@ sub _around_import_domain {
     if ($spinoff) {
         warn "Spinning volumes off their backing files ...\n"
             if $ENV{TERM} && $0 !~ /\.t$/;
-        $domain->spinoff_volumes();
+        $domain->spinoff();
     }
     return $domain;
 }