Without the proposed patch, I get invalid manifests because stderr is added to the revision property. I think this might be something specific to my setup though:
$ java -version Picked up JAVA_TOOL_OPTIONS: -Dfile.encoding=utf8 java version "1.7.0_51" OpenJDK Runtime Environment (fedora-18.104.22.168.fc20-x86_64 u51-b31) OpenJDK 64-Bit Server VM (build 24.51-b03, mixed mode)
since it doesn't seem happen with older java/ant combinations.
Nonetheless, it seems like the right thing is to explicitly ignore stderr.