lava_wait_jobs.py: Clarify retry message

Previous message was rather unclear, print(exc) prints "internal"
argument(s) of an exception, but not even a type of the exception,
so there could be output like:

19:23:45  'PsaApiTest_Crypto'

Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
Change-Id: I8ea8b2580276039d388d9244f6438556c21923a6
diff --git a/lava_helper/lava_wait_jobs.py b/lava_helper/lava_wait_jobs.py
index 0a56f99..f61abab 100755
--- a/lava_helper/lava_wait_jobs.py
+++ b/lava_helper/lava_wait_jobs.py
@@ -261,9 +261,9 @@
             wait_for_jobs(user_args)
             break
         except Exception as e:
-            print(e)
             if try_time < 2:
-                print("Try to get LAVA jobs again...")
+                print("Exception in wait_for_jobs: {!r}".format(e))
+                print("Trying to get LAVA jobs again...")
             else:
                 raise e