ClassCastException at TTextProtocol.readStructBegin when reading ailased enum.

[imasahiro]

Currently it seems TTextProtocol do not support reading ailased enum. When we use DocService with enum, got ClassCastException with following stack trace.

https://gist.github.com/imasahiro/2c02f1b27c4a2068dd06597fd77bb101 is a patch which can reproduce this error.

$ mvn test
(snip)
Tests run: 11, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 0.029 sec <<< FAILURE! - in com.linecorp.armeria.common.thrift.text.TTextProtocolTest
tTextProtocolReadWriteTest(com.linecorp.armeria.common.thrift.text.TTextProtocolTest)  Time elapsed: 0.012 sec  <<< ERROR!

java.lang.ClassCastException: org.apache.thrift.meta_data.FieldValueMetaData cannot be cast to org.apache.thrift.meta_data.EnumMetaData
        at com.linecorp.armeria.common.thrift.text.TTextProtocolTest.tTextProtocolReadWriteTest(TTextProtocolTest.java:90)