Travis CI : legacy => container-based infrastructure

.travis.yml

@@ -9,6 +9,15 @@ git:
 matrix:
   fast_finish: true
 
+addons:
+  apt:
+    packages:
+    - iptables-dev
+    - libevent-dev
+    - libnfnetlink-dev
+
+sudo: false
+
 env:
   - 'PROJECT=minissdpd'
   - 'PROJECT=miniupnpc'
@@ -16,10 +25,6 @@ env:
   - 'PROJECT=miniupnpc-libevent'
   - 'PROJECT=miniupnpd'
 
-before_install:
-  - 'sudo apt-get -qq update'
-  - 'sudo apt-get -qq install iptables-dev libevent-dev libnfnetlink-dev'
-
 script:
   - 'cd $TRAVIS_BUILD_DIR && cd $PROJECT'
   - 'MAKEFILE=Makefile && if [ -a Makefile.linux ]; then MAKEFILE=Makefile.linux; fi'