Update exec unzip with -u option and eliminate web ui extraction every client run

Without the unzip -u chef-client was failing with the following:

```
[2014-05-10T00:16:18+00:00] ERROR: bash[extract consul web_ui] (consul::default line 121) had an error: Mixlib::ShellOut::ShellCommandFailed: Expected process to exit with [0], but received '1'
---- Begin output of "bash"  "/tmp/chef-script20140510-9698-1l4k8dn" ----
STDOUT: Archive:  /tmp/0.2.0_web_ui.zip
STDERR: replace index.html? [y]es, [n]o, [A]ll, [N]one, [r]ename:  NULL
(EOF or read error, treating as "[N]one" ...)
---- End output of "bash"  "/tmp/chef-script20140510-9698-1l4k8dn" ----
Ran "bash"  "/tmp/chef-script20140510-9698-1l4k8dn" returned 1
[2014-05-10T00:16:18+00:00] FATAL: Chef::Exceptions::ChildConvergeError: Chef run process exited unsuccessfully (exit code 1)
```

Also, the web ui was being extracted every chef-client run without the not_if
```
 * bash[extract consul web_ui] action run
    - execute "bash"  "/tmp/chef-script20140510-10008-12qfy4m"
```

A bit redundant between the two but that was the order I encountered them.  Thanks for putting this cookbook together!