Add profiling support to cinderclient

To be able to create profiling traces for Cinder, client should be
able to send special HTTP header that contains trace info.

This patch is as well important to be able to make cross project
traces. (Typical case nova calls cinder via python client, if
profiler is initialized in nova, cinder client will add extra
header, that will be parsed by special osprofiler middleware in cinder
api)

Don't worry no security issue here, trace information is signed by HMAC
key that is setted in api-paste.ini. So only person that knows HMAC key
is able to send proper header.

Main patch (in Cinder) is:
https://review.openstack.org/#/c/103415/

Change-Id: I53bb1b92e62841a02f941bdafaed7f8ed5db7ce1
gitignore /.*

Ignore all dotfiles in the base dir of the tree except for
.gitignore.

This should solve the "ignore my IDE's files" problem in a
general way.

Change-Id: I689220b303d24c65c5fe9523eadc8ad48a93737f
Merge "gitignore /.*"