Raw assertion failure is shown if mpiexec does not exist in mpienv add

[keisukefukuda]

Traceback (most recent call last):
File "/home/kfukuda/.pyenv/versions/3.5.2/lib/python3.5/runpy.py", line 184, in _run_module_as_main
"main", mod_spec)
File "/home/kfukuda/.pyenv/versions/3.5.2/lib/python3.5/runpy.py", line 85, in _run_code
exec(code, run_globals)
File "/mnt/vol10/kfukuda/mpienv/mpienv/command/add.py", line 25, in
main()
File "/mnt/vol10/kfukuda/mpienv/mpienv/command/add.py", line 21, in main
mpienv.add(args.path, args.name)
File "/mnt/vol10/kfukuda/mpienv/mpienv/core.py", line 236, in add
mpi = self.get_mpi_from_mpiexec(target)
File "/mnt/vol10/kfukuda/mpienv/mpienv/core.py", line 166, in get_mpi_from_mpiexec
return mpi_class(mpiexec, self._conf)
File "/mnt/vol10/kfukuda/mpienv/mpienv/openmpi.py", line 22, in init
assert os.path.exists(mpicc)
AssertionError