absPathToExecutable is not in ksb::Util, fix call.

I had thought I had already moved absPathToExecutable into ksb::Util,
but as it turns out I had not done so quite yet.

This caused my bugfix for bug 299577 to instead cause a crash, sorry
about that. :(

BUG:299577

kdesrc-build

@@ -3474,7 +3474,7 @@ EOF
     sub absPathToQMake
     {
         my @possibilities = qw/qmake qmake4 qmake-qt4 qmake-mac/;
-        return grep { absPathToExecutable($_) } @possibilities;
+        return grep { main::absPathToExecutable($_) } @possibilities;
     }
 
     # Return value style: boolean