Repairs compare cluster's counter

Computes counter in brackets when "same" or "diff" filter used

Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1469111

app/controllers/application_controller/compare.rb

@@ -1444,7 +1444,21 @@ def comp_add_total(view)
   def comp_add_section(view, section, records, fields)
     cell_text = _(section[:header])
     if records.nil? # Show records count if not nil
-      cell_text += " (#{fields.length})"
+
+      # If fields are filtered (attributes with same/different values)
+      # number of total fields has to be precomputed
+      fields_length = 0
+      fields.each_with_index do |field, _fidx|
+        @same = true
+        if @compressed  # Compressed
+          comp_add_section_field_compressed(view, section, field)
+        else            # Expanded
+          comp_add_section_field_expanded(view, section, field)
+        end
+        fields_length += 1 if compare_delete_row
+      end
+      @same = true # reset for further processing
+      cell_text += " (#{fields_length})"
     else                # Show fields count
       cell_text += " (#{records.length})"
     end