Subversion and Mercurial bash autocomplete

Summary:
Enable autocomplete both for Subversion and Mercurial
to use with arc shell.

Fixes T637.
Fixes T638.

Test Plan:
Run the container, then type some expressions followed by a <tab>:

• hg clo (for hg clone)
• svn che (for svn checkout)

Reviewers: dereckson

Subscribers: Nasqueron Docker deployment squad

Projects: Docker images

Maniphest Tasks: T637, T638

Differential Revision: http://devcentral.nasqueron.org/D136