Update tag in the Contracts/cse-snapshot test.

Also:
- allow local variables 'repo' and 'tag' to be overridden
  by the optional LocalOverrides.cmake
- print out STATUS messages to see the variable values in
  CMake configure output

Tests/Contracts/cse-snapshot/CMakeLists.txt

@@ -13,8 +13,18 @@ if(NOT DEFINED HOME)
     set(HOME "$ENV{HOME}")
   endif()
 endif()
+message(STATUS "HOME='${HOME}'")
+
+if(NOT DEFINED repo)
+  set(repo "git://public.kitware.com/cse.git")
+endif()
+message(STATUS "repo='${repo}'")
+
+if(NOT DEFINED tag)
+  set(tag "cc1dcb95439a21ab1d58f444d93481598414196e")
+endif()
+message(STATUS "tag='${tag}'")
 
-set(tag "510345e4360ac3b07ddb29e527207297f7cc6d89")
 string(SUBSTRING "${tag}" 0 8 shorttag)
 
 set(base_dir "${HOME}/.cmake/Contracts/${PROJECT_NAME}/${shorttag}")
@@ -25,10 +35,12 @@ set(source_dir "${base_dir}/src")
 if(NOT DEFINED BUILDNAME)
   set(BUILDNAME "CMakeContract-${shorttag}")
 endif()
+message(STATUS "BUILDNAME='${BUILDNAME}'")
 
 if(NOT DEFINED SITE)
   site_name(SITE)
 endif()
+message(STATUS "SITE='${SITE}'")
 
 if(NOT DEFINED PROCESSOR_COUNT)
   # Unknown:
@@ -56,12 +68,14 @@ if(NOT DEFINED PROCESSOR_COUNT)
     set(PROCESSOR_COUNT "$ENV{NUMBER_OF_PROCESSORS}")
   endif()
 endif()
+message(STATUS "PROCESSOR_COUNT='${PROCESSOR_COUNT}'")
 
 find_package(Git)
 if(NOT GIT_EXECUTABLE)
   message(FATAL_ERROR "error: could not find git")
   # adjust PATH to find git, or set GIT_EXECUTABLE in LocalOverrides.cmake
 endif()
+message(STATUS "GIT_EXECUTABLE='${GIT_EXECUTABLE}'")
 
 configure_file(
   "${CMAKE_CURRENT_SOURCE_DIR}/Dashboard.cmake.in"
@@ -83,7 +97,7 @@ else()
   # If it does not yet exist, download clones the git repository:
   ExternalProject_Add(download-${PROJECT_NAME}
     SOURCE_DIR "${source_dir}"
-    GIT_REPOSITORY "git://public.kitware.com/cse.git"
+    GIT_REPOSITORY "${repo}"
     GIT_TAG "${tag}"
     CONFIGURE_COMMAND ""
     BUILD_COMMAND ""