Work around wstool bug in build with Docker base image. (#1041)
Work around wstool bug in build with Docker base image. (#1041)

We have already a cloned source space in the base image, which can be
buggy according to: https://github.com/vcstools/wstool/issues/77

This should unblock Travis and fix local builds.
cartographer-project/cartographer_ros,googlecartographer/cartographer_ros,googlecartographer/cartographer_ros,wohe/cartographer_ros,cartographer-project/cartographer_ros,cartographer-project/cartographer_ros,damonkohler/cartographer_ros,damonkohler/cartographer_ros,damonkohler/cartographer_ros,wohe/cartographer_ros,googlecartographer/cartographer_ros,wohe/cartographer_ros