Allow using an own SSL cert and private key.

Allow using an own SSL cert and private key.

Added two new config options, one for the certificate, one
for the private key. If they are both provided, they are used
by nginx, otherwise, a new certificate is automatically 
generated.

Fixed a pre-existent bug: even if you can specify the 
directory where to store the certificates, this path 
was not used by nginx, because an hardcoded one was
present in the configuration file.

Improved how ssl options are handled in config-changes.
If the SSL path is changed using 'juju set', now that
change is reflected in the nginx config file, and the
service correctly restarted.

Added tests for the process of saving or generating SSL
certificates.

Some code clean up.

Please note that all the SSL stuff is still 
disabled/commented.

https://code.launchpad.net/~frankban/charms/precise/juju-gui/bug-1092515-certificates/+merge/141105

(do not edit description out of merge proposal)

[frankban, 2012-12-21 17:47:13]

Please take a look.

[frankban, 2012-12-21 17:53:32]

Please take a look.

[teknico, 2012-12-21 18:22:43]

Land as is.

Great job.

[matthew.scott, 2012-12-21 20:01:57]

Looks good to me, land as is.

Thanks for the changes.

[gary.poster, 2012-12-21 22:49:06]

I'm distracted that I can't run the tests successfully--part of the problem was
that a new d3 release broke our build, and I asked bac to fix that with a better
package spec--but this looks good and should land.  Thank you!

Gary

[frankban, 2012-12-22 10:51:52]

*** Submitted:

Allow using an own SSL cert and private key.

Added two new config options, one for the certificate, one
for the private key. If they are both provided, they are used
by nginx, otherwise, a new certificate is automatically 
generated.

Fixed a pre-existent bug: even if you can specify the 
directory where to store the certificates, this path 
was not used by nginx, because an hardcoded one was
present in the configuration file.

Improved how ssl options are handled in config-changes.
If the SSL path is changed using 'juju set', now that
change is reflected in the nginx config file, and the
service correctly restarted.

Added tests for the process of saving or generating SSL
certificates.

Some code clean up.

Please note that all the SSL stuff is still 
disabled/commented.

R=teknico, matthew.scott, gary.poster
CC=
https://codereview.appspot.com/6976046