cephtool: accept semicolons in commandline args

cephtool: accept semicolons in commandline args

Semicolons can now be used to give multiple arguments to cephtool in one
invocation. So a command like this is now possible:

$ ./ceph osd dump --format=json \; pg dump --format=json -o -

The backslash is to prevent the shell from consuming the semicolon.

Signed-off-by: Colin McCabe <colin.mccabe@dreamhost.com>