Cleanup: move clear_table() to divesite.c

There were two declaration of clear_table(), one in dive.h and one
in parse.h. The definition was in parse.c. Since the parser doesn't
even use the function, move the function and its declaration to
divelist.[ch] and remove the redundant declaration in dive.h.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

core/divelist.c

@@ -42,6 +42,8 @@
  * bool is_trip_before_after(const struct dive *dive, bool before)
  * void delete_dive_from_table(struct dive_table *table, int idx)
  * int find_next_visible_dive(timestamp_t when);
+ * void clear_dive_file_data()
+ * void clear_table(struct dive_table *table)
  */
 #include <unistd.h>
 #include <stdio.h>
@@ -1683,6 +1685,16 @@ void clear_dive_file_data()
 	saved_git_id = "";
 }
 
+/*
+ * Clear a dive_table
+ */
+void clear_table(struct dive_table *table)
+{
+	for (int i = 0; i < table->nr; i++)
+		free(table->dives[i]);
+	table->nr = 0;
+}
+
 /* This function defines the sort ordering of dives. The core
  * and the UI models should use the same sort function, which
  * should be stable. This is not crucial at the moment, as the