SerializerError is not indented correctly

[ferozed]

Description

he class confluent_kafka.avro.serializer.SerializerError is not authored correctly. The indents are wrong for str and repl methods.

--
https://github.com/confluentinc/confluent-kafka-python/blob/master/confluent_kafka/avro/serializer/__init__.py#L25-L32

This is the result:

--
$ ./bin/python
Python 2.7.15 (default, Jun 17 2018, 13:05:56)
[GCC 4.2.1 Compatible Apple LLVM 9.0.0 (clang-900.0.39.2)] on darwin
Type "help", "copyright", "credits" or "license" for more information.

from confluent_kafka.avro.serializer import SerializerError
s = SerializerError("foo is not bar")
s
SerializerError()
str(s)
''
s.message
'foo is not bar'
--

Expected:

str(s) == 'foo is not bar'

How to reproduce

$ ./bin/python
Python 2.7.15 (default, Jun 17 2018, 13:05:56)
[GCC 4.2.1 Compatible Apple LLVM 9.0.0 (clang-900.0.39.2)] on darwin
Type "help", "copyright", "credits" or "license" for more information.

from confluent_kafka.avro.serializer import SerializerError
s = SerializerError("foo is not bar")
s
SerializerError()
str(s)
''
s.message
'foo is not bar'

Checklist

Please provide the following information:

Not necessary as repro is self contained.

• [X ] confluent-kafka-python and librdkafka version (confluent_kafka.version() and confluent_kafka.libversion()):
• Apache Kafka broker version:
• Client configuration: {...}
• Operating system:
• Provide client logs (with 'debug': '..' as necessary)
• Provide broker log excerpts
• Critical issue

[ferozed]

This is my PR for this issue:

#675

[pranavrth]

Thanks for the contribution.

This PR is merged. Closing the issue.