Introduce new slc5_amd64_gcc462 architecture.

SiteTests/testjob/tests/TestCmsswVersion.sh

@@ -14,9 +14,12 @@ case $cmsver in
     CMSSW_3_[4-9]* | CMSSW_3_1[01]*)
       arch=slc5_ia32_gcc434
       ;;
-    *)
+    CMSSW_4* | CMSSW_5_0*)
       arch=slc5_amd64_gcc434
       ;;
+    *)
+      arch=slc5_amd64_gcc462
+      ;;
 esac
 export SCRAM_ARCH=$arch
 export BUILD_ARCH=$arch