Add support for SL5 builds 3_4_x and beyond.

SiteTests/testjob/tests/TestCmsswVersion.sh

@@ -7,11 +7,11 @@ case $cmsver in
     CMSSW_0* | CMSSW_1_[1-4]*)
       arch=slc3_ia32_gcc323
       ;;
-    CMSSW_1_[5678]*)
+    CMSSW_1_[5678]* | CMSSW_2* | CMSSW_3_[0123]*)
       arch=slc4_ia32_gcc345
       ;;
     *)
-      arch=slc4_ia32_gcc345
+      arch=slc5_ia32_gcc434
       ;;
 esac
 export SCRAM_ARCH=$arch