HadoopDruidIndexer breaks when timestampColumn is not all lowercase

[cheddar]

The Parser converts all the field names into lowercase values, but the HadoopDruidIndexerConfig is not doing the same with the timestampColumn field, so when it looks for the actual column, it breaks with an exception like

Caused by: java.lang.IllegalArgumentException: null timestamp
at com.google.common.base.Preconditions.checkArgument(Preconditions.java:88)
at com.metamx.common.parsers.TimestampParser$5.apply(TimestampParser.java:119)
at com.metamx.common.parsers.TimestampParser$5.apply(TimestampParser.java:115)
at com.metamx.druid.indexer.IndexGeneratorJob$IndexGeneratorMapper.map(IndexGeneratorJob.java:189)

[fjy]

should be fixed when spatial is merged