dpkg: Remove extra newline from path filter debug output

The debug() function automatically appends a newline, no need to
duplicate it.

src/filters.c

@@ -48,7 +48,7 @@ filter_add(const char *pattern, bool include)
 {
 	struct filter_node *filter;
 
-	debug(dbg_general, "adding %s filter for '%s'\n",
+	debug(dbg_general, "adding %s filter for '%s'",
 	      include ? "include" : "exclude", pattern);
 
 	filter = m_malloc(sizeof(*filter));