sshutils: reload scp object if transport is not active

The SCPClient stores a reference to an active transport but does not
attempt to reconnect it if the connection is lost. Updated SSHClient's
'scp' property to also reload the SCPClient in the case that the
transport is not active.

closes gh-119
tests: remove aws_credentials_validation test

This test eventually should be moved to a 'live' tests module that
requires AWS credentials, network connection, and runs using real money
and resources. Removing this test until a 'live' tests module exists
given that all default tests should be purely local and not require an
account or network access.

https://bugs.gentoo.org/show_bug.cgi?id=426528

closes gh-121
config: use chmod 600 when writing config template

Updated exception.ConfigNotFound.create_config to call chmod 600 after
writing the config template. This makes it so that only the owner of the
file can view its contents which is important given that the config
template will eventually contain AWS security credentials.

closes gh-144
cluster: reraise uncaught exceptions in run_plugins

Reraise uncaught exceptions in Cluster.run_plugins instead of logging an
error (along with the fullstack trace) and continuing running other
plugins.
scimage: copy scimage.py to scimage_11_10.py

In preparation for updating scimage.py for latest Ubuntu 12.04 (precise)
scimage: add method to recompile/install openblas
scimage: update hadoop to cdh3u5
scimage: add mosh to default packages
scimage: use custom openblas with NumPy/SciPy
scimage: update header comments for 12.04 (precise)
scimage: remove redundant git install

git is already installed in the install_default_packages method
scimage: add default-jdk to default package list
scimage: fix typo in default package list
scimage: remove pyzmq==2.1.9 requirement

This was a bug in IPython's version checking that appears to be fixed in
0.13.
scimage: update MOTD for latest 12.04 AMIs
scimage: update chroot mounting instructions

Include dbus mount which is necessary in order to upgrade dbus within a
Ubuntu chroot. Also add instructions for mounting sysfs and devpts.
scimage: disable upstart during build

Disabled as a part of setup_environ() and re-enabled in cleanup()
scimage: install missing libltdl dep for condor

The deb package must be manually downloaded to /usr/local/src for now.
scimage: build OpenBlas with NO_AFFINITY=1

NO_AFFINITY=1 is required to utilize all cores on all non
cluster-compute/GPU instance types due to the shared virtualization
layer not supporting processor affinity properly. However, Cluster
Compute/GPU instance types use a near-bare-metal hypervisor which *does*
support processor affinity. From minimal testing it appears that there
is a ~20% increase in performance when using affinity on cc1/cg1 types
implying NO_AFFINITY=1 should *not* be set for cluster compute/GPU AMIs.
scimgdeploy: pep8 cleanup