Index bug in parallel

The following minimal example produces an index out of bounds error when executed by sufficiently many processes in parallel:

from dolfin import *
mesh = UnitSquareMesh(100, 100)
gamma = BoundaryMesh(mesh, "exterior")
F = VectorFunctionSpace(gamma, "DG", 0)
V = Function(F)

If I execute the above with less than 7 processes everything is fine. With 8 or more processes I get the error below. I suppose the mesh partitioning has produced a situation where there is at least one process that does not own a piece of the physical boundary...

Number of global vertices: 10201
Number of global cells: 20000
Warning: Mesh is empty, unable to create entities of dimension 1.
Warning: Mesh is empty, unable to create entities of dimension 1.
Traceback (most recent call last):
File "FenicsCrash.py", line 6, in <module>
F = VectorFunctionSpace(gamma, "DG", 0)
File "/home/schmidt/FEniCS/lib64/python2.7/site-packages/dolfin/functions/functionspace.py", line 628, in init
constrained_domain=constrained_domain)
File "/home/schmidt/FEniCS/lib64/python2.7/site-packages/dolfin/functions/functionspace.py", line 168, in init dolfin_dofmap = cpp.DofMap(ufc_dofmap, mesh)
File "/home/schmidt/FEniCS/lib64/python2.7/site-packages/dolfin/cpp/fem.py", line 653, in init _fem.DofMap_swiginit(self,_fem.new_DofMap(*args)) RuntimeError:

-------------------------------------------------------------------------
DOLFIN encountered an error. If you are not able to resolve this issue
*** using the information listed below, you can ask for help at

*** fenics@fenicsproject.org

Remember to include the error message listed below and, if possible,
include a minimal running example to reproduce the error.

-------------------------------------------------------------------------
Error: Unable to create mesh entity.
Reason: Mesh entity index 0 out of range [0, 0] for entity of dimension 1.
Where: This error was encountered inside MeshEntity.cpp.
*** Process: unknown

DOLFIN version: 1.4.0+
Git changeset: db040f8f7f4a78497dd891bbd515c31528f37141
*** -------------------------------------------------------------------------

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