suite: Print process ending prematurely

Change-Id: Icec476ccc536611f771dcc7872f5190bbd0572e7
diff --git a/src/osmo_gsm_tester/suite.py b/src/osmo_gsm_tester/suite.py
index 66d06fa..c4a9abc 100644
--- a/src/osmo_gsm_tester/suite.py
+++ b/src/osmo_gsm_tester/suite.py
@@ -379,7 +379,7 @@
                     process.log_stdout_tail()
                     process.log_stderr_tail()
                     log.ctx(process)
-                    raise log.Error('Process ended prematurely')
+                    raise log.Error('Process ended prematurely: %s' % process.name())
 
     def prompt(self, *msgs, **msg_details):
         'ask for user interaction. Do not use in tests that should run automatically!'