getPartitionDescFromPath() in CombineHiveInputFormat should handle matching by path

The use case is:

dir = hdfs://host:9000/user/warehouse/tableName/abc
pathToPartitionInfo = {/user/warehouse/tableName : myPart}

Then calling

 
getPartitionDescFromPath(dir, pathToPartitionInfo)

will throw an IOException because /user/warehouse/tableName is not a prefix of hdfs://host:9000/user/warehouse/tableName/abc. Currently, this is not an issue but will come up if CombineFileInputFormat is modified so what the scheme and authority are not stripped out when generating splits (see MAPREDUCE-1806).

The proposed solution is add a case where matching is done by just the path component of the URI's.