The ADO Statement assumes that the statement has been executed by the time finish gets called.  This patch adds a simple
nil check before finishing the result handle.

Repro:

DBI.connect('DBI:ADO:Provider=SQLNCLI;Data Source=[server];database=[db];Integrated Security=SSPI') do |dbh|
  dbh.prepare("SELECT 1") do |sth|
    #do nothing with sth
  end
end

patch with:
>patch -up 0 -i ado.patch