ITS#9068 fix backslash escaping

mdb_load wasn't properly inserting escaped backslashes into the data.
mdb_dump wasn't escaping backslashes when generating printable output.

external/db_drivers/liblmdb/mdb_dump.c

@@ -64,6 +64,8 @@ static void text(MDB_val *v)
 	end = c + v->mv_size;
 	while (c < end) {
 		if (isprint(*c)) {
+			if (*c == '\\')
+				putchar('\\');
 			putchar(*c);
 		} else {
 			putchar('\\');