i18n: calculate correct line number in source of messages to be translated Before this patch, line number in source of the message to be translated is wrong in hg.pot, if corresponded message is placed after ".. DIRECTIVE::", because number of lines related to such directive isn't added to variable "delta", which holds number of untranslated lines in given text. This patch always adds "2" to "delta", because text block is split into translation units by "\n\n".