ovs-vsctl-bashcomp: Add bash command-line completion for ovs-vsctl.

This patch adds bash command-line completion script for ovs-vsctl.
Therein, codes are added to ovs-vsctl to allow it to print the
options and command arguments.  The ovs-vsctl-bashcomp.bash will
parse the vsctl command and complete on the user input.

The completion script can do the following::

- display available completions and complete on user input for
  global/local options, sub-commands, and arguments.

- query database and expand keywords like 'table/record/column/key'
  to available completions.

- deal with argument relations like 'one and more', 'zero or one'.

- complete multiple ovs-vsctl commands cascaded via '--'.

To use the script, either copy it inside /etc/bash_completion.d/
or manually run it via . ovs-vsctl-bashcomp.bash.

Signed-off-by: Peter Amidon <peter@picnicpark.org>
Signed-off-by: Alex Wang <alexw@nicira.com>
Acked-by: Ben Pfaff <blp@nicira.com>

AUTHORS

@@ -302,6 +302,7 @@ Pankaj Thakkar          thakkar@nicira.com
 Pasi Kärkkäinen         pasik@iki.fi
 Paulo Cravero           pcravero@as2594.net
 Pawan Shukla            shuklap@vmware.com
+Peter Amidon            peter@picnicpark.org
 Peter Balland           peter@nicira.com
 Peter Phaal             peter.phaal@inmon.com
 Prabina Pattnaik        Prabina.Pattnaik@nechclst.in

utilities/automake.mk

@@ -30,6 +30,7 @@ docs += utilities/ovs-command-bashcomp.INSTALL.md
 EXTRA_DIST += \
 	utilities/ovs-check-dead-ifs.in \
 	utilities/ovs-appctl-bashcomp.bash \
+	utilities/ovs-vsctl-bashcomp.bash \
 	utilities/ovs-command-bashcomp.INSTALL.md \
 	utilities/ovs-ctl.in \
 	utilities/ovs-dev.py \