changed UG installation path

[[Imported from SVN: r1778]]

grid/uggrid/undefAllMacros.pl

 #!/usr/bin/perl -w
 
 # TODO: Detect location of UG from the DUNE build system
-$UGROOT = "../../../UG/ug";
+$UGROOT = "../../../uginst";
 
 # Counts the total number of #undefs emitted
 $counter = 0;