Only change login umask when needed

src/freedombone-utils-setup

 }
 
 function set_login_umask {
-    sed -i 's|UMASK\t.*|UMASK\t\t077|g' /etc/login.defs
+    if ! grep -q 'UMASK\t\t077' /etc/login.defs; then
+        sed -i 's|UMASK\t.*|UMASK\t\t077|g' /etc/login.defs
+    fi
 }
 
 function disable_deferred_execution {