Fix the installation of the CLI depenendencies

The previous command could make the installation process stuck
sometimes. This patch modifies 015.install_midonet_cli.sh to
install the depenendencies of the CLI for sure.

Change-Id: I7d56b05038586823bf5964116905c36431d068fc
Signed-off-by: Taku Fukushima <tfukushima@midokura.com>