Fix pip install pkgs with non-ascii characters in filenames

As found recently, pip with Python 3.6 and forward has some issues
installing tarballs that contain files with non-ascii characters
in their names.
This is due mainly to the fact that the default locale in the
system is set to C [1].
As a workaround, we run the installation of the packages in the
virtualenv forcing C.UTF-8 locale.

[1] pypa/pip#7667

Change-Id: Idfb8b121a43a0bb74844fd63d5c2507d7b888b15

dib/ironic-python-agent-ramdisk/install.d/ironic-python-agent-ramdisk-source-install/60-ironic-python-agent-ramdisk-install

@@ -6,6 +6,8 @@ fi
 set -eu
 set -o pipefail
 
+export LC_ALL=C.UTF-8
+
 SCRIPTDIR=$(dirname $0)
 IPADIR=/tmp/ironic-python-agent
 UPPER_CONSTRAINTS=/tmp/requirements/upper-constraints.txt