make copy_file() a bit easier to understand, and smaller

function                                             old     new   delta
copy_file                                           1565    1447    -118
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-118)           Total: -118 bytes
   text    data     bss     dec     hex filename
 770938    1063   10788  782789   bf1c5 busybox_old
 770814    1063   10788  782665   bf149 busybox_unstripped

1 files changed, 0 insertions, 2 deletions

diff --git a/libbb/inode_hash.c b/libbb/inode_hash.c
index 69e39af63..9cca74bcb 100644
--- a/libbb/inode_hash.c
+++ b/libbb/inode_hash.c
@@ -84,6 +84,4 @@ void reset_ino_dev_hashtable(void)
         free(ino_dev_hashtable);
         ino_dev_hashtable = NULL;
 }
-#else
-void reset_ino_dev_hashtable(void);
 #endif