Glanceclient is trying to create ~/.glanceclient, and crashes if it can't
do that. In some environment (for example, when building the package
under Jenkins), writing on $HOME is simply not allowed, and Glanceclient
can simply ignore it. This patch allows the mkdir() to fail, which fixes
the issue.
Closes-Bug: #1446096
Change-Id: Ib3591fb4e54ccd2fe63a1a4815551ac10ef5b961