[SPARK-5462] [SQL] Use analyzed query plan in DataFrame.apply()

This patch changes DataFrame's `apply()` method to use an analyzed query plan when resolving column names.  This fixes a bug where `apply` would throw "invalid call to qualifiers on unresolved object" errors when called on DataFrames constructed via `SQLContext.sql()`.

Author: Josh Rosen <joshrosen@databricks.com>

Closes #4282 from JoshRosen/SPARK-5462 and squashes the following commits:

b9e6da2 [Josh Rosen] [SPARK-5462] Use analyzed query plan in DataFrame.apply().