modify install script

uninstall.sh

 #!/bin/bash
-if [ "$(pwd | grep -c 'filebeat')" -gt 0 ]; then echo "script location is incorrect, run me in filebeat installation directory"; fi
+if [ "$(pwd | grep -c 'filebeat')" -lt 0 ]; then echo "script location is incorrect, run me in filebeat installation directory"; exit 1; fi
 source ./util.sh
 sudo systemctl disable filebeat 2>/dev/null
 sudo systemctl stop filebeat 2>/dev/null