Fix path in TF-slim README
Fix path in TF-slim README

The cloned slim directory is found in `$HOME/workspace/models/slim`,
not `$HOME/workspace/slim`.

bousmalis/models,derekjchow/models,derekjchow/models,xcyan/models,xcyan/models,jiaphuan/models,zbigniewwojna/text-rcnn,wangyang59/tf_models,hang-qi/models,jiaphuan/models,cshallue/models,jazcollins/models,jch1/models,bousmalis/models,jazcollins/models,cshallue/models,tombstone/models,r888888888/models,tombstone/models,derekjchow/models,bousmalis/models,hang-qi/models,r888888888/models,derekjchow/models,hang-qi/models,cshallue/models,r888888888/models,jiaphuan/models,jiaphuan/models,jiaphuan/models,hang-qi/models,tombstone/models,wangyang59/tf_models,r888888888/models,xcyan/models,jazcollins/models,tombstone/models,alexgorban/models,alexgorban/models,jch1/models,sshleifer/object_detection_kitti,jch1/models,sshleifer/object_detection_kitti,wangyang59/tf_models,r888888888/models,jch1/models,bousmalis/models,wangyang59/tf_models,xcyan/models,jazcollins/models,jazcollins/models,sshleifer/object_detection_kitti,r888888888/models,jazcollins/models,hang-qi/models,xcyan/models,cshallue/models,derekjchow/models,wangyang59/tf_models,alexgorban/models,hang-qi/models,sshleifer/object_detection_kitti,tombstone/models,jiaphuan/models,sshleifer/object_detection_kitti,jch1/models,bousmalis/models,cshallue/models,bousmalis/models,jch1/models,sshleifer/object_detection_kitti,alexgorban/models,tombstone/models,alexgorban/models,wangyang59/tf_models,xcyan/models