Trying to publish a CSV file without a schema results in exception

[rufuspollock]

Try with dp1 fixture data and you get:

Traceback (most recent call last):
  File "/Users/rgrp/.virtualenvs/fd/bin/dpmpy", line 4, in <module>
    sys.exit(cli())
  File "/Users/rgrp/.virtualenvs/fd/lib/python2.7/site-packages/click/core.py", line 716, in __call__
    return self.main(*args, **kwargs)
  File "/Users/rgrp/.virtualenvs/fd/lib/python2.7/site-packages/click/core.py", line 696, in main
    rv = self.invoke(ctx)
  File "/Users/rgrp/.virtualenvs/fd/lib/python2.7/site-packages/click/core.py", line 1060, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/Users/rgrp/.virtualenvs/fd/lib/python2.7/site-packages/click/core.py", line 889, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/Users/rgrp/.virtualenvs/fd/lib/python2.7/site-packages/click/core.py", line 534, in invoke
    return callback(*args, **kwargs)
  File "/Users/rgrp/src/frictionlessdata/dpm-py/dpm/main.py", line 45, in wrapped
    return f(*args, **kwargs)
  File "/Users/rgrp/src/frictionlessdata/dpm-py/dpm/main.py", line 157, in publish
    puburl = client.publish()
  File "/Users/rgrp/src/frictionlessdata/dpm-py/dpm/client/__init__.py", line 128, in publish
    self.validate()
  File "/Users/rgrp/src/frictionlessdata/dpm-py/dpm/client/__init__.py", line 114, in validate
    report = validate_data(self.datapackage)
  File "/Users/rgrp/src/frictionlessdata/dpm-py/dpm/client/__init__.py", line 348, in validate_data
    'schema': Schema(resource.descriptor['schema']),
KeyError: u'schema'

Reason is our data validation is trying to find a scheme and one isn't there.