test suite: a few missing import fixes

test/test_py_d/ts_misc.py

@@ -20,7 +20,7 @@
 test.test_py_d.ts_misc: Miscellaneous test groups for the test.py test suite
 """
 
-import re,time
+import sys,os,re,time
 
 from mmgen.cfg import gc
 from mmgen.util import ymsg

test/test_py_d/ts_shared.py

@@ -26,7 +26,7 @@ from mmgen.util import ymsg,get_extension
 from mmgen.wallet import get_wallet_cls
 
 from ..include.common import cmp_or_die,strip_ansi_escapes,joinpath
-from .common import ref_bw_file
+from .common import ref_bw_file,ref_bw_hash_preset,ref_dir
 
 class TestSuiteShared(object):
 	'shared methods for the test.py test suite'