sstable: remove filter name check when copying filter

This check is not correct, as the file we are copying can have a
different filter policy than the level it's going to. I can reproduce
a meta test failure on master. I am not sure why it only started
failing now.

Removing the check is ok because we are resetting
`w.filter/w.filterBlock`, so it doesn't matter what it was initialized
to.

Author: RaduBerinde

sstable/colblk_writer.go

@@ -1263,9 +1263,6 @@ func (w *RawColumnWriter) addDataBlock(b, sep []byte, bhp block.HandleWithProper
 // by the sstable copier that can copy parts of an sstable to a new sstable,
 // using CopySpan().
 func (w *RawColumnWriter) copyFilter(filter []byte, filterName string) error {
-	if w.filterBlock != nil && filterName != w.filterBlock.policyName() {
-		return errors.Newf("mismatched filters %q vs %q", filterName, w.filterBlock.policyName())
-	}
 	w.filterBlock = copyFilterWriter{
 		origPolicyName: w.filterBlock.policyName(), origMetaName: w.filterBlock.metaName(), data: filter,
 	}

sstable/rowblk_writer.go

@@ -1973,9 +1973,6 @@ func (w *RawRowWriter) copyProperties(props Properties) {
 
 // copyFilter implements RawWriter.
 func (w *RawRowWriter) copyFilter(filter []byte, filterName string) error {
-	if w.filter != nil && filterName != w.filter.policyName() {
-		return errors.Newf("mismatched filters %q vs %q", filterName, w.filter.policyName())
-	}
 	w.filter = copyFilterWriter{
 		origPolicyName: w.filter.policyName(), origMetaName: w.filter.metaName(), data: filter,
 	}