Switch path during upgrades

src/freedombone-app-peertube

     function_check set_repo_commit
     set_repo_commit $PEERTUBE_DIR "peertube commit" "$PEERTUBE_COMMIT" $PEERTUBE_REPO
 
-    alias npm-exec='PATH=$(npm bin):$PATH'
-    npm-exec npm run upgrade-peertube
+    PREV_PATH=$PATH
+    PATH=$(npm bin):$PATH
+    npm run upgrade-peertube
+    PATH=$PREV_PATH
 
     chown -R peertube:peertube $PEERTUBE_DIR
     systemctl start peertube