travis: Install six Python library.

The travis-ci build is broken because the Python six library is not
installed.

Signed-off-by: Russell Bryant <russell@ovn.org>
Tested-by: Joe Stringer <joe@ovn.org>
Acked-by: Joe Stringer <joe@ovn.org>

diff --git a/.travis/prepare.sh b/.travis/prepare.sh
index cfc1b17..752be9f 100755 (executable)
--- a/.travis/prepare.sh
+++ b/.travis/prepare.sh
@@ -2,3 +2,4 @@
 
 git clone git://git.kernel.org/pub/scm/devel/sparse/chrisl/sparse.git
 cd sparse && make && make install && cd ..
+pip install --disable-pip-version-check --user six