chain_xattr.cc: fix memory leak, free 'expected'

Fix for:
[src/test/objectstore/chain_xattr.cc:186]: (error) Memory leak:
 expected

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
MDBalancer.cc: remove some since 2009 unused code

Remove some since long time unused code and variables (commented out
since 2009).

Fix for:

[src/mds/MDBalancer.cc:757]: (style) Variable 'total_sent' is
 assigned a value that is never used.
[src/mds/MDBalancer.cc:665]: (style) Variable 'total_goal' is
 assigned a value that is never used.

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>