tests: log error which happens during connect and wait longer for stats socket

Intermittently, a test would start VPP, but no testcases would execute.
This would be more probable apparent during the high load or if there
is another testcase dumping the core at that moment.
Adding the logging to the connection revealed it was the stats socket
connection erroring with error -2. Increasing the deadline
from 3 seconds to 5 minutes has eliminated this error.

Change-Id: I40bd7e642abb9e2aef0238c612e4c34781de5db2
Signed-off-by: Andrew Yourtchenko <ayourtch@gmail.com>
Type: test

test/framework.py

@@ -451,7 +451,7 @@ class VppTestCase(unittest.TestCase):
 
     @classmethod
     def wait_for_stats_socket(cls):
-        deadline = time.time() + 3
+        deadline = time.time() + 300
         ok = False
         while time.time() < deadline or \
                 cls.debug_gdb or cls.debug_gdbserver:
@@ -570,7 +570,8 @@ class VppTestCase(unittest.TestCase):
                                    "VPP-API connection failed, did you forget "
                                    "to 'continue' VPP from within gdb?", RED))
                 raise
-        except Exception:
+        except Exception as e:
+            cls.logger.debug("Exception connecting to VPP: %s" % e)
 
             cls.quit()
             raise