travis-ci /etc/hosts workaround

ci/travis-prepare.sh

@@ -6,9 +6,18 @@ die() {
   exit 1
 }
 
-
 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 "===="