Add profiling support to Trove client

To be able to create profiling traces for Trove, 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 horizon calls Trove via python client, if
profiler is initialized, Trove client will add extra header, that
will be parsed by special osprofiler middleware in Trove 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 Trove is: I580cce8d2b3c4ec9ce625ac09de6f14e1249f6f5

We prepared a common BP in oslo-spec due to integration change is
similar to all projects: I95dccdc9f274661767d2659c18b96da169891f30
Currently there are 2 other projects are using osprofiler: Glance &
Cinder, and some others are working in progress.

Change-Id: I5a76e11d428c63d33f6d2c2021426090ebf8340c
Signed-off-by: Zhi Yan Liu <zhiyanl@cn.ibm.com>