Tests fail for centos7 configuration

[brandjon]

This error occurs in a clean checkout locally but not in travis.

Testing virtualenv tests/requirements-test-centos7.txt
Already using interpreter /usr/bin/python3
Using base prefix '/usr'
New python executable in /usr/local/google/home/brandjon/src/blah/subpar/.env/bin/python3
Also creating executable in /usr/local/google/home/brandjon/src/blah/subpar/.env/bin/python
Installing setuptools, pkg_resources, pip, wheel...done.
Collecting setuptools==0.9.8 (from -r tests/requirements-test-centos7.txt (line 2))
  Using cached https://files.pythonhosted.org/packages/51/20/7b9e9cc363f176d9c3f1c4570e8ed8654ceba5cf3b0022d06add2f0e36ae/setuptools-0.9.8-py2.py3-none-any.whl
Installing collected packages: setuptools
  Found existing installation: setuptools 41.0.1
    Uninstalling setuptools-41.0.1:
      Successfully uninstalled setuptools-41.0.1
Successfully installed setuptools-0.9.8
INFO: Starting clean (this may take a while). Consider using --async if the clean takes more than several minutes.
INFO: Analyzed 62 targets (32 packages loaded, 687 targets configured).
INFO: Found 32 targets and 30 test targets...
ERROR: /usr/local/google/home/brandjon/.cache/bazel/_bazel_brandjon/f0064f73a7ea36f3e834106b5eca1fe4/external/test_workspace/BUILD:32:1: Building par file @test_workspace//:test_compiler_label.par failed (Exit 1) compiler.par failed: error executing command bazel-out/host/bin/external/subpar/compiler/compiler.par --manifest_file bazel-out/k8-fastbuild/bin/external/test_workspace/test_compiler_label.par_SOURCES --output_par ... (remaining 6 argument(s) skipped)

Use --sandbox_debug to see verbose messages from the sandbox
Traceback (most recent call last):
  File "/usr/lib/python3.6/runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "/usr/lib/python3.6/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "bazel-out/host/bin/external/subpar/compiler/compiler.par/__main__.py", line 19, in <module>
  File "bazel-out/host/bin/external/subpar/compiler/compiler.par/subpar/runtime/support.py", line 326, in setup
  File "bazel-out/host/bin/external/subpar/compiler/compiler.par/subpar/runtime/support.py", line 157, in _setup_pkg_resources
  File "/usr/local/google/home/brandjon/src/blah/subpar/.env/lib/python3.6/site-packages/pkg_resources.py", line 1545, in <module>
    register_loader_type(importlib_bootstrap.SourceFileLoader, DefaultProvider)
AttributeError: module 'importlib._bootstrap' has no attribute 'SourceFileLoader'