contrib: fix cddb mistakenly depending on iconv

Currently there are two issues here, one hiding the other:

- The sed pattern is wrong, causing it to not match due to leading
  spaces.
- The replacement for the second sed pattern is wrong, not removing
  the @LIBICONV@, causing it to be present in the generated .pc, but
  due to the previous issue, this was hidden as the iconv detection was
  never actually removed.

This issue only rarely manifested, as we also build iconv in contribs,
so it was totally depending on build order if this caused any issue or
not.

contrib/src/cddb/rules.mak

@@ -26,9 +26,9 @@ cddb: libcddb-$(CDDB_VERSION).tar.bz2 .sum-cddb
 	$(APPLY) $(SRC)/cddb/no-gettext.patch
 	# Avoid relying on iconv.m4 from gettext, when reconfiguring.
 	# This is only used by the frontend which we disable.
-	sed -i.orig 's/^AM_ICONV/#&/' $(UNPACK_DIR)/configure.ac
+	sed -i.orig 's/^[[:blank:]]*AM_ICONV/#&/' $(UNPACK_DIR)/configure.ac
 	# add internal dependencies
-	sed -i.orig 's/-lcddb @LIBICONV@/-lcddb @LIBICONV@ @LIBS@/' $(UNPACK_DIR)/libcddb.pc.in
+	sed -i.orig 's/-lcddb @LIBICONV@/-lcddb @LIBS@/' $(UNPACK_DIR)/libcddb.pc.in
 	$(MOVE)
 
 DEPS_cddb = regex $(DEPS_regex)