Update arm Ubuntu cross build docker image

Now, use:

microsoft/dotnet-buildtools-prereqs:ubuntu-14.04-cross-e435274-20180323032140

diff --git a/netci.groovy b/netci.groovy
index 9186459..620ceb8 100755 (executable)
--- a/netci.groovy
+++ b/netci.groovy
@@ -985,7 +985,7 @@ def static getDockerImageName(def architecture, def os, def isBuild) {
         }
         else if (architecture == 'arm') {
             if (os == 'Ubuntu') {
-                return "microsoft/dotnet-buildtools-prereqs:ubuntu-14.04-cross-0cd4667-20170319080304"
+                return "microsoft/dotnet-buildtools-prereqs:ubuntu-14.04-cross-e435274-20180323032140"
             }
         }
     }