Return proper error message when network conflicts

Fixes bug 1158075
When creating a network which is already existing, we got
an internal server error which can't show the error reason.
This patch returns conflict error(HTTP 409) instead of
internal server error(HTTP 500), so that users can know
the error reason from the error message.

Change-Id: I9e39a7152e37756b34b1c8d77de057012743f0f7
(cherry picked from commit 8a80c4c0968a9deceaa6d99629c6d7f7889769e5)
Fix the filtered characters list from console-log

In fffcaea1 ^M was added to the list of characters to filter from the
console-log output but, because of a typo in the regexp, the
character '-' was added to that list too and has been removed since
then.

Fixes bug #1194032

Change-Id: Ia02b0b4c7027cbd09a51042ca1b5d28890413626
(cherry picked from commit c651f4928c65407cff86a9f9efc046a0f76a9519)
Merge "Fix the filtered characters list from console-log" into stable/grizzly
Merge "Return proper error message when network conflicts" into stable/grizzly
Merge branch 'stable/grizzly' of https://github.com/openstack/nova into grizzly/stable