Fix svn fetch_revision error

Escape backslash of `sed` command argument. Close #1061
Use `svn log -l 1` to get the last revision of working directory.
`svn log -r HEAD` outputs empty result if the working directory
is a subdirectory in the repository and a directory outside the
working directory has latest revision.

`svn log -l 1` shows only the first 1 log message.
The default revision range for a local path is BASE:1.
http://svnbook.red-bean.com/en/1.7/svn.ref.svn.c.log.html
Improve Server Property handling

* Deep copy properties added using the 'roles' keyword
* If a property exists on a server when another definition is
encountered and is an Array, Set or Hash then add the new values

This allows roles to specify properties common to all servers and
then for individual servers to modify them, keeping things DRY

See example in: spec/lib/capistrano/configuration/servers_spec.rb:31
Remove -v from mkdir options
Update .travis.yml

Stop travis running a build for the legacy-v2 branch.
Ensure capistrano CLI options override rake's

rake's implementation of #sort_options was ordering
cap's version of --dry-run first, rake's second.
During option parsing, this meant rake's was added last,
so it overwrote cap's.

This adjustment makes sure capistrano wins these battles.
Merge remote-tracking branch 'upstream/master'

Conflicts:
	CHANGELOG.md
Tweak CHANGELOG.md to force another build
Merge pull request #1130 from townsen/server_props

Improve server property handling
Improve handling of defaults for :set variables

Added set_if_empty method to DSL to allow conditional setting
of variables.

Altered standard Capistrano defaults so that they are not set
at the start of a stage if they have been previously set. This
allows variables like :default_env to be set in deploy.rb.
Merge pull request #1127 from mtwentyman/master

Ensure capistrano CLI options override rake's
Merge pull request #1026 from caligo-mentis/openbsd_compatibility_fix

Remove -v from mkdir options
Merge pull request #1070 from shirosaki/svn_fetch_revision

Fix svn fetch_revision error
replaced suggestion in config/deploy.rb to re-implement restart task for passenger with a suggestion to use capistrano-passenger gem