Add an option in lib/swift to increase max_header_size

With the increasing number of entries in the service_catalog header,
some projects will have a header bigger than 8192 and Swift cannot
handle headers of this size. Solum is the first one to have this issue

As a temporary hack to fix Solum's gate, we are increasing
the value of the max_header_size parameter in our "lib" script.

This patch makes this settings global to all projects using devstack,
so that in a near future, if a project has a service_catalog header
bigger than 8192, it doesn't have the same problems we had.

Closes bug 1316585

Change-Id: I5c15f8f9531839353c3d99e46d920688058ec33c
Use urandom rather than openssl for password gen

I tried using devstack on a cloud image that didn't have openssl, so
it generated blank passwords and gave an error about openssl missing.
Using urandom should not require more than minimal shell tools.

Change-Id: Ib3091183eb1d85fc8cf7c76e47da24a04ae4791f
Merge "Use urandom rather than openssl for password gen"
Merge "Add an option in lib/swift to increase max_header_size"