allow to use install module via luarocks

luarocks knows nothing about "tarantool". So it's reasonable to
drop it at all from dependencies.

See also tarantool/vshard@e2df019

Author: olegrok

crud-scm-1.rockspec

@@ -6,8 +6,7 @@ source  = {
 }
 
 dependencies = {
-    'tarantool',
-    'lua >= 5.1',
+    'lua ~> 5.1',
     'checks == 3.1.0-1',
     'errors == 2.1.3-1',
     'vshard == 0.1.16-1',