Fix unset variable error for CHECK_GRASS_EXTRA_INCLUDE_DIRS macro

Author: dakcarto

cmake/FindGRASS.cmake

@@ -136,7 +136,7 @@ MACRO (CHECK_GRASS G_PREFIX)
           SET(GRASS_FOUND${GRASS_FIND_VERSION} TRUE)
           SET(GRASS_FOUND TRUE) # GRASS_FOUND is true if at least one version was found
           SET(GRASS_PREFIX${GRASS_CACHE_VERSION} ${G_PREFIX})
-          CHECK_GRASS_EXTRA_INCLUDE_DIRS(${GRASS_CACHE_VERSION})
+          CHECK_GRASS_EXTRA_INCLUDE_DIRS(${GRASS_FIND_VERSION})
           IF(GRASS_FIND_VERSION EQUAL 6)
             # Set also normal variable with number
             SET(GRASS_INCLUDE_DIR${GRASS_FIND_VERSION} ${GRASS_INCLUDE_DIR${GRASS_CACHE_VERSION}})