Handle errors with force encoding

Some ES errors cause Encoding::CompatibilityError: incompatible character encodings: UTF-8 and ASCII-8BIT

I am able to duplicate this by starting ES with the following setting:

indices.query.query_string.allowLeadingWildcard: false

Then issue the following query:

client.search({query: {query_string: {query: "*.運動會"}}}, {index: 'test'})