Removed a ignore shellcheck comment in zzz_evobackup and fix warning

Since only one PID can be in the PID file, we will never have more than one, we can thus easily quote the variable and remove the shellcheck ignore.

zzz_evobackup

@@ -123,9 +123,7 @@ pick_server() {
 if [ -e "${PIDFILE}" ]; then
     pid=$(cat "${PIDFILE}")
     # Does process still exist ?
-    # ignore check because multiple processes might exist
-    # shellcheck disable=SC2086
-    if kill -0 ${pid} 2> /dev/null; then
+    if kill -0 "${pid}" 2> /dev/null; then
         # Killing the childs of evobackup.
         for ppid in $(pgrep -P "${pid}"); do
             kill -9 "${ppid}";