Change sudo apt-get installs to travis.yml packages

Author: mwcraig

.continuous-integration/travis/setup_environment_linux.sh

@@ -7,12 +7,8 @@ chmod +x miniconda.sh
 export PATH=/home/travis/miniconda/bin:$PATH
 conda update --yes conda
 
-# Install non-Python dependencies for documentation
-if [[ $SETUP_CMD == build_sphinx* ]]
-then
-  sudo apt-get update
-  sudo apt-get install graphviz texlive-latex-extra dvipng
-fi
+# Installation of non-Python dependencies for documentation is now
+# in .travis.yml
 
 # Install Python dependencies
 source "$( dirname "${BASH_SOURCE[0]}" )"/setup_dependencies_common.sh

.travis.yml

@@ -9,6 +9,14 @@ os:
 # Setting sudo to false opts in to Travis-CI container-based builds.
 sudo: false
 
+# The apt packages below are needed for sphinx builds, which can no longer
+# be installed with sudo apt-get.
+addons:
+    apt:
+        packages:
+            - graphviz
+            - texlive-latex-extra
+            - dvipng
 env:
     global:
         # Set defaults to avoid repeating in most cases