Switch scripts to use Python 3

Issue https://github.com/apache/couchdb/issues/1632
diff --git a/bin/apt-dependencies.sh b/bin/apt-dependencies.sh
index 1b177e2..07f1d5a 100755
--- a/bin/apt-dependencies.sh
+++ b/bin/apt-dependencies.sh
@@ -60,8 +60,9 @@
 apt-get -y dist-upgrade
 
 # install build-time dependencies
-apt-get install -y apt-transport-https curl git pkg-config python \
-    libpython-dev python-pip sudo wget zip unzip \
+apt-get install -y apt-transport-https curl git pkg-config \
+    python3 libpython3-dev python3-pip \
+    sudo wget zip unzip \
     build-essential ca-certificates libcurl4-openssl-dev \
     libicu-dev libnspr4-dev
 
@@ -78,11 +79,11 @@
 
 # fix for broken sphinx on ubuntu 12.04 only
 if [[ ${VERSION} == "precise" ]]; then
-  pip install docutils==0.13.1 sphinx==1.5.3
+  pip3 install docutils==0.13.1 sphinx==1.5.3
 fi
 
 # rest of python dependencies
-pip install --upgrade sphinx_rtd_theme nose requests hypothesis==3.79.0
+pip3 install --upgrade sphinx_rtd_theme nose requests hypothesis==3.79.0
 
 # package-building stuff
 apt-get install -y curl debhelper devscripts dh-exec dh-python \
diff --git a/bin/yum-dependencies.sh b/bin/yum-dependencies.sh
index 4819c0a..e763abf 100755
--- a/bin/yum-dependencies.sh
+++ b/bin/yum-dependencies.sh
@@ -89,9 +89,10 @@
   wget https://bootstrap.pypa.io/get-pip.py -O /tmp/get-pip.py
   /usr/bin/python3.4 /tmp/get-pip.py
 else
-  yum install -y python-pip
+  yum install -y python34-pip python-virtualenv
 fi
-pip install docutils==0.13.1 sphinx==1.5.3 sphinx_rtd_theme \
+
+pip3 install docutils==0.13.1 sphinx==1.5.3 sphinx_rtd_theme \
     nose requests hypothesis==3.79.0
 
 # package-building stuff