pex_wrapper.pex failed when I run the first invocation - second invocation works successfully

[kramasamy]

 bazel build heron/...
INFO: Found 2 targets...
ERROR: /Users/karthikz/workspace/connectors/heron/spouts/pulsar/src/python/BUILD:12:1: null failed: pex_wrapper.pex failed: error executing command bazel-out/host/bin/external/io_bazel_rules_pex/pex/pex_wrapper.pex --pex-root .pex --entry-point heron.spouts.pulsar.src.python.pulsar_spout --output-file ... (remaining 4 argument(s) skipped): com.google.devtools.build.lib.shell.BadExitStatusException: Process exited with status 1.
Traceback (most recent call last):
  File ".bootstrap/_pex/pex.py", line 326, in execute
  File ".bootstrap/_pex/pex.py", line 258, in _wrap_coverage
  File ".bootstrap/_pex/pex.py", line 290, in _wrap_profiling
  File ".bootstrap/_pex/pex.py", line 369, in _execute
  File ".bootstrap/_pex/pex.py", line 427, in execute_entry
  File ".bootstrap/_pex/pex.py", line 432, in execute_module
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/runpy.py", line 180, in run_module
    fname, loader, pkg_name)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/runpy.py", line 72, in _run_code
    exec code in run_globals
  File "/private/var/tmp/_bazel_karthikz/fa631bb0f7ae8f36398ceb2660e4c283/execroot/connectors/.pex/install/pex_wrapper-0.1-py2-none-any.whl.bce01df26c502f8e244b96dc2f1e4682854a40a0/pex_wrapper-0.1-py2-none-any.whl/pex_wrapper.py", line 109, in <module>
    main()
  File "/private/var/tmp/_bazel_karthikz/fa631bb0f7ae8f36398ceb2660e4c283/execroot/connectors/.pex/install/pex_wrapper-0.1-py2-none-any.whl.bce01df26c502f8e244b96dc2f1e4682854a40a0/pex_wrapper-0.1-py2-none-any.whl/pex_wrapper.py", line 63, in main
    resolver_options_builder)
  File "/private/var/tmp/_bazel_karthikz/fa631bb0f7ae8f36398ceb2660e4c283/execroot/connectors/.pex/install/pex-1.1.14-py2.py3-none-any.whl.8350b5e3ea62522c62fc3adc036502afbb66b0d3/pex-1.1.14-py2.py3-none-any.whl/pex/bin/pex.py", line 489, in build_pex
    resolveds = resolver.resolve(resolvables)
  File "/private/var/tmp/_bazel_karthikz/fa631bb0f7ae8f36398ceb2660e4c283/execroot/connectors/.pex/install/pex-1.1.14-py2.py3-none-any.whl.8350b5e3ea62522c62fc3adc036502afbb66b0d3/pex-1.1.14-py2.py3-none-any.whl/pex/resolver.py", line 200, in resolve
    dist = self.build(package, resolvable.options)
  File "/private/var/tmp/_bazel_karthikz/fa631bb0f7ae8f36398ceb2660e4c283/execroot/connectors/.pex/install/pex-1.1.14-py2.py3-none-any.whl.8350b5e3ea62522c62fc3adc036502afbb66b0d3/pex-1.1.14-py2.py3-none-any.whl/pex/resolver.py", line 263, in build
    os.rename(target + '~', target)
OSError: [Errno 2] No such file or directory
INFO: Elapsed time: 18.596s, Critical Path: 13.09s