seeker: turn off debug logging

The debug log is only revealed when something goes wrong, but it is
created and discarded every time `seek_backward` is called, and it
is quite CPU-intensive.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>

include/crucible/seeker.h

@@ -8,7 +8,7 @@
 
 #include <cstdint>
 
-#if 1
+#if 0
 #include <iostream>
 #include <sstream>
 #define DINIT(__x) __x