patch for statx calls on Docker should not be required anymore on Bionic

.ci/travis/docker_image/before_install.sh

@@ -13,12 +13,3 @@
 #   (at your option) any later version.                                   #
 #                                                                         #
 ###########################################################################
-
-if [[ ${INSTALL_LIBSECCOMP} =~ ^TRUE$ ]]; then
-  # When building QGIS with Qt 5.10+ in a Docker container, statx calls are required on the host
-  # see https://bugs.launchpad.net/ubuntu/+source/docker.io/+bug/1755250
-  # this is required on Xenial (currently most recent distribution on Travis), but sould not on Bionic+
-  wget https://launchpad.net/ubuntu/+archive/primary/+files/libseccomp2_2.4.1-0ubuntu0.16.04.2_amd64.deb
-  sudo dpkg -i libseccomp2_2.4.1-0ubuntu0.16.04.2_amd64.deb
-  sudo apt-get install -f
-fi

.travis.yml

@@ -127,7 +127,6 @@ matrix:
         - TRIGGER_PYQGIS_DOC=TRUE
         - DOCKER_TAG="$( echo $TRAVIS_BRANCH | sed 's/master/latest/' )_disco"
         - DOCKER_BUILD_DEPS_FILE=qgis3-build-deps-disco.dockerfile
-        - INSTALL_LIBSECCOMP=TRUE
         - CC=/usr/lib/ccache/gcc
         - CXX=/usr/lib/ccache/g++ # Building SIP binding freezes with Clang in Docker, maybe a SIP issue, maybe not