correct path for install check

tests/check_install.sh

 #!/bin/bash
 rc=0;
 if [[ ! -z "${GROUP_DIR}" ]]; then
-    cd delphi
+    cd ${GROUP_DIR}
     epawx11=2
     # check Motif CERN apps
     fpawx11=`find . -name pawX11 | wc -l`