EnvInject squelches changes to $BUILD_DISPLAY_NAME made by build name setter plugin

When envinject and build name setter are installed together, changes to the build display name made with BNS are no longer reflected in the $BUILD_DISPLAY_NAME var. Instead this var evaluates to the default #JOB_NO format.

The build name setter appears to still do it's job as the job history pane in jenkins reflects the updated name, it's just the var reference does not evaluate to the updated name.

Note that this occurs just by having envinject installed, so we've had to disable it.