environs/sshstorage: fix intermittent test failure

The initial "bash" command was changed at some
point from being all-on-the-command-line to bash
executing a script on stdin. The test changes to
reflect that.

Fixes https://bugs.launchpad.net/juju-core/+bug/1323898
Revert "Merge pull request #12 from voidspace/refresh-rate"

This reverts commit 0f58c7c42bdac68e9635528ce3ebd111b272f3f9, reversing
changes made to 594bf710e5f4f3c723cad0a99f1c218df5d3d655.
Merge pull request #11 from axw/sshstorage-test-failure

The initial "bash" command was changed at some point from being all-on-the-command-line to bash executing a script on stdin. The test changes to reflect that.

Fixes https://bugs.launchpad.net/juju-core/+bug/1323898
Backout replicaset changes causing precise CI problems
Merge pull request #14 from voidspace/backout-replicaset-changes