[GRASS] fixed cmake build with G7 without G6

Author: blazek

src/providers/CMakeLists.txt

@@ -22,6 +22,6 @@ IF (POSTGRES_FOUND)
   ADD_SUBDIRECTORY(postgres)
 ENDIF (POSTGRES_FOUND)
 
-IF (WITH_GRASS)
+IF (WITH_GRASS OR WITH_GRASS7)
   ADD_SUBDIRECTORY(grass)
-ENDIF (WITH_GRASS)
+ENDIF (WITH_GRASS OR WITH_GRASS7)