travis: ignore errors from apt-get

also run 'apt-get upgrade' after 'apt-get update'.
move apt-related commands to travis_install_deps.sh

.travis.yml

@@ -31,11 +31,9 @@ matrix:
 install:
  - deactivate
  - export VER=$TRAVIS_PYTHON_VERSION$DEBUGPY
- - sudo apt-get update -qq
- - sudo apt-get install -q python$VER
  - export PYTHON=/usr/bin/python$VER
- - echo $PYTHON && $PYTHON --version
  - sudo -E ./travis_install_deps.sh
+ - echo $PYTHON && $PYTHON --version
  - sudo $PYTHON setup.py install
 script:
  - cd greentest && $PYTHON testrunner.py --full --expected ../known_failures.txt
@@ -45,4 +43,3 @@ notifications:
       - denis.bilenko@gmail.com
     on_success: change
     on_failure: change
-

travis_install_deps.sh

 #!/bin/sh
 set -e -x
+apt-get update -yqq || true
+apt-get upgrade -yqq || true
+apt-get install -q python$VER
 if [ "x$VER" = "x2.5" ]; then apt-get install libssl-dev libkrb5-dev libbluetooth-dev; curl -sSLO --retry 5 --fail http://pypi.python.org/packages/source/s/sslfix/sslfix-1.15.tar.gz; fi
 curl -sSLO --retry 5 --fail https://github.com/downloads/denik/packages/python2.7-cython_0.17.1_i386.deb
 curl -sSLO --retry 5 --fail https://github.com/downloads/denik/packages/python$VER-greenlet_0.4.0_i386.deb