travis: fix /etc/hosts issue on bionic image

travis/prepare.sh

@@ -29,6 +29,23 @@ CACHEDIR=${CACHEDIR:-${HOME}/.cache}
 
 echo -e "${ANSI_YELLOW}Using bash version $BASH_VERSION${ANSI_RESET}"
 
+if [ -f /etc/hosts ]
+then
+    # The travis-ci "bionic" image throws us a curveball in /etc/hosts
+    # by including two entries for localhost.  The first for 127.0.1.1
+    # which causes epicsSockResolveTest to fail.
+    #  cat /etc/hosts
+    #  ...
+    #  127.0.1.1 localhost localhost ip4-loopback
+    #  127.0.0.1 localhost nettuno travis vagrant travis-job-....
+
+    sudo sed -i -e '/^127\.0\.1\.1/ s|localhost\s*||g' /etc/hosts
+
+    echo "==== /etc/hosts"
+    cat /etc/hosts
+    echo "===="
+fi
+
 # Load settings
 # -------------