memcached: Be more paranoid in buffer allocation
memcached: Be more paranoid in buffer allocation

Summary: Not likely to be an actual problem, but we were making room for 6 numbers and rendering 8 into a buffer.

Reviewed By: hzhao

Test Plan: memcached test suite passes


git-svn-id: d16fc8af3894fe4b8f00d9e752b9e158f74a7d75@73647 2c7ba8d8-a2f7-0310-a573-de162e16dcc7

sysalexis/memcached,sysalexis/memcached,sysalexis/memcached,sysalexis/memcached,sysalexis/memcached