Fix build failure caused by missing 'gerrit-plugin-gwtui:client' target

In bb360ebe the target '//gerrit-plugin-gwtui:client' was renamed to
'//gerrit-plugin-gwtui:gwtui-api', but the 'tools/eclipse/BUCK' and
'tools/gwt-constants.defs' files were not updated to use it, thus
running 'tools/eclipse/project' failed with a "No such build target"
error.

Change-Id: I72307de9bac2484722b666ac0f5d0c0bb99b3906
2 files changed