Allow silent failures on some perm denied ops.

Allow silent failures on some perm denied ops.

Some operations are not allowed in read-only mode, but, per user input, permission denied errors are not necessarily helpful.  This prevents the notifications from being created, but still prevents the operation, and still logs to the console.

https://code.launchpad.net/~makyo/juju-gui/update-annotations-fix/+merge/163033

(do not edit description out of merge proposal)

[matthew.scott, 2013-05-08 18:41:20]

Please take a look.

[jeff.pihach, 2013-05-08 19:17:52]

LGTM - Thanks for this fix! 

I would like to see a follow-up task to create an event type and and then move
this check into the notifications code to enable a single place to allow the
user to disable notifications from a certain type and have a single point of
filtering in the code.

[bac, 2013-05-08 19:18:17]

LGTM

[matthew.scott, 2013-05-08 20:21:56]

*** Submitted:

Allow silent failures on some perm denied ops.

Some operations are not allowed in read-only mode, but, per user input,
permission denied errors are not necessarily helpful.  This prevents the
notifications from being created, but still prevents the operation, and still
logs to the console.

R=jeff.pihach, bac
CC=
https://codereview.appspot.com/9307043