[SPARK-21785][SQL]Support create table from a parquet file schema

[jinshen-cn]

Support create table from a parquet file schema

As described in jira:

CREATE EXTERNAL TABLE IF NOT EXISTS test LIKE 'PARQUET' '/user/test/abc/a.snappy.parquet' STORED AS PARQUET LOCATION
'/user/test/def/'; 

this is a very ugly fix and I would like someone to help to review and refine.
and it only supports create hive table with schema from parquet file.

Tested by test case and tested about build the runnable distribution

test("create table like parquet") {

    val f = getClass.getClassLoader.
      getResource("test-data/dec-in-fixed-len.parquet").getPath
    val v1 =
      """
        |create table if not exists db1.table1 like 'parquet'
      """.stripMargin.concat("'" + f + "'").concat(
      """
        |stored as sequencefile
        |location '/tmp/table1'
      """.stripMargin
      )

    val (desc, allowExisting) = extractTableDesc(v1)

    assert(allowExisting)
    assert(desc.identifier.database == Some("db1"))
    assert(desc.identifier.table == "table1")
    assert(desc.tableType == CatalogTableType.EXTERNAL)
    assert(desc.schema == new StructType()
      .add("fixed_len_dec", "decimal(10,2)"))
    assert(desc.bucketSpec.isEmpty)
    assert(desc.viewText.isEmpty)
    assert(desc.viewDefaultDatabase.isEmpty)
    assert(desc.viewQueryColumnNames.isEmpty)
    assert(desc.storage.locationUri == Some(new URI("/tmp/table1")))
    assert(desc.storage.inputFormat == Some("org.apache.hadoop.mapred.SequenceFileInputFormat"))
    assert(desc.storage.outputFormat == Some("org.apache.hadoop.mapred.SequenceFileOutputFormat"))
    assert(desc.storage.serde == Some("org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe"))
  }

[maropu]

@crazyjacky Can you close this for now cuz it's not active for a long time?

[AmplabJenkins]

Can one of the admins verify this patch?