zdtm.py: pass a test PID into zdtm hooks

travis-ci: success for series starting with [01/21] build: install libnet-dev
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

test/zdtm.py

@@ -1005,14 +1005,18 @@ def cr(cr_api, test, opts):
 
 		sbs('pre-dump')
 
+		os.environ["ZDTM_TEST_PID"] = str(test.getpid())
 		if opts['norst']:
+			try_run_hook(test, ["--pre-dump"])
 			cr_api.dump("dump", opts = ["--leave-running"])
 		else:
+			try_run_hook(test, ["--pre-dump"])
 			cr_api.dump("dump")
 			test.gone()
 			sbs('pre-restore')
 			try_run_hook(test, ["--pre-restore"])
 			cr_api.restore()
+			os.environ["ZDTM_TEST_PID"] = str(test.getpid())
 			try_run_hook(test, ["--post-restore"])
 			sbs('post-restore')