Merge pull request pyca#2011 from reaperhulk/tox-env-versions

list package versions in tox env for easier debugging

tox.ini

@@ -11,6 +11,7 @@ deps =
     ./vectors
 passenv = ARCHFLAGS LDFLAGS CFLAGS INCLUDE LIB LD_LIBRARY_PATH
 commands =
+    pip list
     python -c "from cryptography.hazmat.backends.openssl.backend import backend; print(backend.openssl_version_text())"
     # We use parallel mode and then combine here so that coverage.py will take
     # the paths like .tox/py34/lib/python3.4/site-packages/cryptography/__init__.py
@@ -47,13 +48,15 @@ commands =
 # coverage.py on pypy.
 [testenv:pypy]
 commands =
+    pip list
     python -c "from cryptography.hazmat.backends.openssl.backend import backend; print(backend.openssl_version_text())"
     py.test --capture=no --strict {posargs}
 
 # Temporarily disable coverage on pypy3 because of performance problems with
 # coverage.py on pypy3.
 [testenv:pypy3]
 commands =
+    pip list
     python -c "from cryptography.hazmat.backends.openssl.backend import backend; print(backend.openssl_version_text())"
     py.test --capture=no --strict {posargs}