KafkaAdmin raises UnsupportedVersion for client-side errors

[jeffwidman]

UnsupportedVersionError is intended to indicate a server-side error:

kafka-python/kafka/errors.py

Lines 375 to 378 in ba7372e

	class UnsupportedVersionError(BrokerResponseError):
	errno = 35
	message = 'UNSUPPORTED_VERSION'
	description = 'The version of API is not supported.'

But the new KafkaAdmin class is raising it client-side, without triggering it from the broker... for example:

• kafka-python/kafka/admin/kafka.py

  Line 30 in 9d44e3c

  versions that are not supported by the broker will result in UnsupportedVersionError exceptions.

• kafka-python/kafka/admin/kafka.py

  Lines 249 to 251 in 9d44e3c

  	raise UnsupportedVersionError(
  	"Kafka Admin interface not supported for cluster controller version {} < 0.10.0.0"
  	.format(version))

I understand that semantically this seems like the appropriate error to raise. However, this is confusing when debugging... for a real-life example, see Parsely/pykafka#697. So I strongly feel that we should keep the server-side errors separate from client-side errors, even if all the client is doing is proactively protecting against hitting a situation where the broker would return this error.

I'm not sure of the right exception to raise, probably we should create a new one.