clone if dir does not exist

utils/nightly/gmsh.ctest

@@ -27,7 +27,7 @@ set(CTEST_GIT_REPOS http://gitlab.onelab.info/gmsh/gmsh.git)
 
 if(NOT EXISTS "${CTEST_SOURCE_DIRECTORY}")
   set(CTEST_CHECKOUT_COMMAND 
-      "${CTEST_GIT_COMMAND} pull ${CTEST_GIT_REPOS} ${CTEST_SOURCE_DIRECTORY}")
+      "${CTEST_GIT_COMMAND} clone ${CTEST_GIT_REPOS} ${CTEST_SOURCE_DIRECTORY}")
 endif(NOT EXISTS "${CTEST_SOURCE_DIRECTORY}")
 set(CTEST_UPDATE_COMMAND "${CTEST_GIT_COMMAND}")