fix: Trap exit code (#592)

src/power.sh

@@ -98,7 +98,6 @@ terminal() {
 
 _graceful_shutdown() {
 
-  local cnt=0
   local code=$?
   local pid url response
 
@@ -144,6 +143,8 @@ _graceful_shutdown() {
 
   fi
 
+  local cnt=0
+
   while [ "$cnt" -lt "$QEMU_TIMEOUT" ]; do
 
     ! isAlive "$pid" && break