Make sure the pip in the virtualenv is upgraded.

Additionally, list the installed packages after each of the two installation
phases.

.travis.yml

@@ -36,7 +36,6 @@ python:
   - 3.4
 
 before_install:
-    - pip install -U pip
     - source tools/travis_before_install.sh
 
     - which python; python --version

tools/travis_before_install.sh

@@ -49,6 +49,7 @@ fi
 virtualenv -p python ~/venv
 source ~/venv/bin/activate
 
+pip install --upgrade pip
 pip install --retries 3 -q wheel flake8 coveralls nose
 
 # on Python 3.2, use matplotlib 1.3.1
@@ -64,6 +65,8 @@ pip install --retries 3 -q $WHEELHOUSE $WHEELS
 
 pip install --retries 3 -q -r requirements.txt
 
+# Show what's installed
+pip list
 
 section () {
     echo -en "travis_fold:start:$1\r"

tools/travis_script.sh

@@ -47,6 +47,9 @@ if [[ $PY == 2.* ]]; then
     pip install --retries 3 -q pyamg
 fi
 
+# Show what's installed
+pip list
+
 section_end "Install.optional.dependencies"