Add travis-wheels as trusted host

tools/drone_before_install.sh

@@ -1,7 +1,7 @@
 #!/usr/bin/env bash
 set -ex
 
-export WHEELHOUSE="--no-index --find-links=http://travis-wheels.scikit-image.org/"
+export WHEELHOUSE="--no-index --trusted-host travis-wheels.scikit-image.org --find-links=http://travis-wheels.scikit-image.org/"
 export PIP_DEFAULT_TIMEOUT=60
 sudo service xvfb start
 export DISPLAY=:99.0
@@ -15,7 +15,6 @@ retry () {
     local count=$retry_max
     while [ $count -gt 0 ]; do
         "$@" && break
-        cat /home/ubuntu/.pip/pip.log || echo "No pip log"
         count=$(($count - 1))
         sleep 1
     done
@@ -31,17 +30,16 @@ sudo apt-get install python-numpy python-scipy python-networkx cython \
                      python-six python-tk
 
 virtualenv -p python --system-site-packages ~/venv
-
 source ~/venv/bin/activate
+
 retry pip install --upgrade setuptools pip
-python -c 'import setuptools; print("Setuptools version:", setuptools.__version__)'
 retry pip install wheel flake8 coveralls nose
 retry pip install $WHEELHOUSE -r requirements.txt
+
 # clean up disk space
 sudo apt-get clean
 sudo rm -rf /tmp/*
 
 export retry
 
 set +ex
-