tests: Increase timeout for test_isolate_from_socket_default_timeout

Increase the timeout used for test_isolate_from_socket_default_timeout
from 1 second to 5 seconds.  Otherwise, the test can't succeed
on hardware where Python runs slower.  In particular, on our SPARC box
importing greenlet modules takes almost 2 seconds, so the test program
does not even start properly.

Fixes eventlet#614

tests/tpool_test.py

@@ -366,7 +366,7 @@ def test_leakage_from_tracebacks(self):
 
 
 def test_isolate_from_socket_default_timeout():
-    tests.run_isolated('tpool_isolate_socket_default_timeout.py', timeout=1)
+    tests.run_isolated('tpool_isolate_socket_default_timeout.py', timeout=5)
 
 
 def test_exception_leak():