update travis

- drop libustr-dev from package list, as the SELinux userland tools dropped this build dependency
 - switch to container based build environments
 - drop unnecessary make flags

.travis.yml

@@ -25,12 +25,7 @@ env:
   - TYPE=mls DISTRO=gentoo MONOLITHIC=y SYSTEMD=n WERROR=y
   - TYPE=mls DISTRO=gentoo MONOLITHIC=n SYSTEMD=n WERROR=y
 
-# Uncomment to use Travis-CI container infrastructure (https://docs.travis-ci.com/user/ci-environment/)
-#sudo: false
-#dist: trusty  # libustr-dev not whitelisted for trusty
-
-# Uncomment these two lines to use Travis-CI Trusty Beta environment
-sudo: required
+sudo: false
 dist: trusty
 
 cache:
@@ -46,7 +41,6 @@ addons:
     - gettext
     - libaudit-dev
     - libbz2-dev
-    - libustr-dev
     - libpcre3-dev
     - swig
 
@@ -61,7 +55,6 @@ install:
   - SELINUX_USERSPACE_VERSION=libsepol-2.7
 
   - export DESTDIR="${TRAVIS_BUILD_DIR}/selinux"
-  - export EXPLICIT_MAKE_VARS="CFLAGS=-I$DESTDIR/usr/include LDFLAGS=-L$DESTDIR/usr/lib LDLIBS= CPPFLAGS= OPT_SUBDIRS=semodule-utils"
   - |
       if [[ "${SELINUX_USERSPACE_VERSION}" != "$(cat ${TRAVIS_BUILD_DIR}/selinux/travis.version)" ]]; then
         rm -fR selinux-src
@@ -83,9 +76,7 @@ install:
         sed -i -e 's/ sandbox//' selinux-src/policycoreutils/Makefile
 
         # Compile and install SELinux toolchain into ~/selinux
-        # On Ubuntu 12.04, default CFLAGS make the build fail in libsepol/cil with:
-        #    error: declaration of 'index' shadows a global declarationo
-        make $EXPLICIT_MAKE_VARS -C selinux-src install
+        make OPT_SUBDIRS=semodule-utils -C selinux-src install
         echo "${SELINUX_USERSPACE_VERSION}" > "${TRAVIS_BUILD_DIR}/selinux/travis.version"
       fi