PBR Freeze reports duplicate shas on many packages.

If I install latest python-heatclient in a clean virtualenv running pbr freeze shows duplicate shas for many packages that should not have any shas.

~/src/openstack$ git clone https://git.openstack.org/openstack/python-heatclient
~/src/openstack$ cd python-heatclient/
~/src/openstack/python-heatclient (master)$ virtualenv venv
~/src/openstack/python-heatclient (master %)$ venv/bin/pip install .
~/src/openstack/python-heatclient (master %)$ venv/bin/pbr freeze
Python==2.7
argparse==1.2.1
wsgiref==0.1.2
oslo.i18n==1.1.0
pytz==2014.10
netifaces==0.10.4 # git sha d6d5197
oslo.utils==1.1.0
pip==1.5.4
prettytable==0.7.2 # git sha d6d5197
python-keystoneclient==1.0.0 # git sha 10860db
Babel==1.3
oslo.serialization==1.1.0
setuptools==2.2
netaddr==0.7.12 # git sha d6d5197
PyYAML==3.11 # git sha d6d5197
six==1.8.0
iso8601==0.1.10 # git sha d6d5197
requests==2.5.1
pbr==0.10.7 # git sha aef4f7e
python-heatclient==0.2.12.post49 # git sha d6d5197
stevedore==1.1.0
oslo.config==1.5.0

See shas on netifaces, prettytable, netaddr, PyYAML, and iso8601. It is the same sha as python-heatclient.