Every Ceph CLI that is invoked at present passes the key via the
--key option, and hence is exposed to key being displayed on
the host using a ps command or such means.
This commit addresses this issue by stashing the key in a tmp
file, which is again created on a tmpfs (or empty dir backed by
memory). Further using such tmp files as arguments to the --keyfile
option for every CLI that is invoked.
This prevents the key from being visible as part of the argument list
of the invoked program on the system.
Fixes: #318
Signed-off-by: ShyamsundarR <srangana@redhat.com>