Address Checkstyle violations
JCLOUDS-622: remove calls to InputSupplier methods

Guava 16 deprecated these methods and Guava 18 will remove them.
JCLOUDS-629: SshjSshClient Payload without length

sshj treats -1 as an unknown length and uses a less efficient copying
mechanism.
JCLOUDS-40: Unasync OpenStack Nova API