Fix propose_update.sh
Fix propose_update.sh

The propose-requirements-updates was failing since we essentially call
virtualenv `mktemp` - but mktemp creates a file and virtualenv expects a
directory.

Add -d to mktemp invocation to create a directory.

Change-Id: I358bd2c42d698de4d7863ac08318d46a4524e32b

Tesora/tesora-project-config,anbangr/osci-project-config,noorul/os-project-config,coolsvap/project-config,openstack-infra/project-config,coolsvap/project-config,dongwenjuan/project-config,dongwenjuan/project-config,anbangr/osci-project-config,noorul/os-project-config,Tesora/tesora-project-config,openstack-infra/project-config