zdtm: fix flake8 warnings

flake8 --config=scripts/flake8.cfg test/zdtm.py
test/zdtm.py:66:1: E305 expected 2 blank lines after class or function definition, found 1
test/zdtm.py:127:1: E305 expected 2 blank lines after class or function definition, found 1
test/zdtm.py:971:1: E305 expected 2 blank lines after class or function definition, found 1
test/zdtm.py:1618:1: E305 expected 2 blank lines after class or function definition, found 1
Makefile:377: recipe for target 'lint' failed

travis-ci: success for zdtm: fix flake8 warnings
Signed-off-by: Andrei Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

test/zdtm.py

@@ -61,6 +61,7 @@ def make_tests_root():
 		atexit.register(clean_tests_root)
 	return tests_root[1]
 
+
 # Report generation
 
 report_dir = None
@@ -123,6 +124,7 @@ def check_core_files():
 
 	return True
 
+
 # Arch we run on
 arch = os.uname()[4]
 
@@ -955,6 +957,7 @@ def try_run_hook(test, args):
 		if hook.wait() != 0:
 			raise test_fail_exc("hook " + " ".join(args))
 
+
 #
 # Step by step execution
 #
@@ -1608,6 +1611,7 @@ def run_tests(opts):
 		if opts['join_ns']:
 			subprocess.Popen(["ip", "netns", "delete", "zdtm_netns"])
 
+
 sti_fmt = "%-40s%-10s%s"