reiserfs: fix "new_insert_key may be used uninitialized ..."

reiserfs: fix "new_insert_key may be used uninitialized ..."

BugLink: http://bugs.launchpad.net/bugs/1629386
commit 0a11b9aae49adf1f952427ef1a1d9e793dd6ffb6 upstream.

new_insert_key only makes any sense when it's associated with a
new_insert_ptr, which is initialized to NULL and changed to a
buffer_head when we also initialize new_insert_key.  We can key off of
that to avoid the uninitialized warning.

Link: http://lkml.kernel.org/r/5eca5ffb-2155-8df2-b4a2-f162f105efed@suse.com
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Jan Kara <jack@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>