Update System.Data for mono/2017-12

Context: dotnet/android#1263

The mono/2017-12 bump introduced a "breaking" change to System.Data:

	<h3>Type Changed: Microsoft.SqlServer.Server.SqlDataRecord</h3>
	<p>Removed method:</p>
	<pre>
	  <span class='removed removed-method breaking' data-is-breaking>public virtual System.Data.IDataReader GetData (int);</span>
	</pre>

There is no `public` `SqlDataRecord.GetData(int)` method documented at
[MSDN](https://msdn.microsoft.com/en-us/library/microsoft.sqlserver.server.sqldatarecord(v=vs.110).aspx).
(There is an explicitly implemented `IDataRecord.GetData(int)` method
which is documented, which the new `System.Data.dll` also contains.)

This is an acceptable ABI break.

Other reported breakage is more likely a defect in `mono-api-html`, as
these are all `override` removals:

	<h3>Type Changed: System.Data.SqlClient.SqlConnectionStringBuilder</h3>
	<p>Removed property:</p>
	<pre>
	  <span class='removed removed-property breaking' data-is-breaking>public bool IsFixedSize { get; }</span>
	</pre>

	<h3>Type Changed: System.Data.SqlClient.SqlParameterCollection</h3>
	<p>Removed properties:</p>
	<pre>
	  <span class='removed removed-property breaking' data-is-breaking>public bool IsFixedSize { get; }</span>
	  <span class='removed removed-property breaking' data-is-breaking>public bool IsReadOnly { get; }</span>
	  <span class='removed removed-property breaking' data-is-breaking>public bool IsSynchronized { get; }</span>
	</pre>

Override removals are not ABI breaks.