Ceph

We should guard all calls to decode_base64:

Program received signal SIGABRT, Aborted.
0x00007ffff72d0a75 in raise () from /lib/libc.so.6
(gdb) bt
#0  0x00007ffff72d0a75 in raise () from /lib/libc.so.6
#1  0x00007ffff72d45c0 in abort () from /lib/libc.so.6
#2  0x00007ffff636f8e5 in __gnu_cxx::__verbose_terminate_handler() () from /usr/lib/libstdc++.so.6
#3  0x00007ffff636dd16 in ?? () from /usr/lib/libstdc++.so.6
#4  0x00007ffff636dd43 in std::terminate() () from /usr/lib/libstdc++.so.6
#5  0x00007ffff636de3e in __cxa_throw () from /usr/lib/libstdc++.so.6
#6  0x00007ffff7b4937e in ceph::buffer::list::decode_base64 (this=<value optimized out>, e=<value optimized out>) at common/buffer.cc:1039
#7  0x00007ffff7a792ad in CryptoKey::decode_base64(std::string const&) () from /usr/lib/librados.so.2
#8  0x00007ffff7a783de in KeyRing::from_ceph_context (cct=0x603530, pkeyring=0x60d248) at auth/KeyRing.cc:64
#9  0x00007ffff7b03d24 in MonClient::init (this=0x60cdc8) at mon/MonClient.cc:357
#10 0x00007ffff7a2bf29 in librados::RadosClient::connect (this=0x60cab0) at librados.cc:965
#11 0x0000000000400875 in main ()
(gdb)