Paxos.h: fix dangerouse use of c_str()

No need to use c_str() in get_statename(), simply return a
std::strin instead.

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
Client.cc: don't pass c_str() if std::string is expected

Don't pass c_str() to _lookup(). The function expect a std::string
as second parameter.

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
Merge pull request #71 from dalgaaf/wip-da-sca-c_str

fix some c_str() usage

Reviewed-by: Sage Weil <sage@inktank.com>