remove_index silently fails when passed a symbol as the index name

When removing an index, if a symbol is used for the index name the removal silently fails.

remove_index :my_table, :name => 'my_index_name'

works but

remove_index :my_table, :name => :my_index_name

does not work. The index removal fails because SchemaStatements#index_name_exists? uses == without first calling to_s on the passed name, so it compares a string with a symbol.

The issue is compounded by the swallowing of the exception, however this has since been fixed by http://github.com/rails/rails/commit/37de59eacf8f6478e866309615af73...

I have attached a patch to fix the problem