Problem: Valgrind in Ubuntu Precise is too old

Solution: run Travis CI in newer Trusty (14.04 LTS) release.

.travis.yml

@@ -6,6 +6,8 @@ os:
 - linux
 - osx
 
+dist: trusty
+
 env:
 - BUILD_TYPE=default CURVE=tweetnacl
 - BUILD_TYPE=android CURVE=tweetnacl
@@ -22,12 +24,10 @@ matrix:
     -  env: BUILD_TYPE=valgrind CURVE=tweetnacl
        os: osx
 
-sudo: false
+sudo: required
 
 addons:
   apt:
-    sources:
-    - kubuntu-backports
     packages:
     - cmake
     - lcov
@@ -40,7 +40,7 @@ before_script:
 # ZMQ stress tests need more open socket (files) than the usual default
 # On OSX, it seems the way to set the max files limit is constantly changing, so
 # try to use all known knobs to ensure compatibility across various versions
-- if [ $TRAVIS_OS_NAME == "osx" ] ; then sudo sysctl -w kern.maxfiles=64000 ; sudo sysctl -w kern.maxfilesperproc=64000 ; sudo launchctl limit maxfiles 64000 64000 ; fi ; ulimit -n 64000
+- if [ $TRAVIS_OS_NAME == "osx" ] ; then sudo sysctl -w kern.maxfiles=64000 ; sudo sysctl -w kern.maxfilesperproc=64000 ; sudo launchctl limit maxfiles 64000 64000 ; ulimit -n 64000; fi
 
 # Build and check this project according to the BUILD_TYPE
 script: ./ci_build.sh