ubuntu: update regex pattern

There is a case that
http://packages.ubuntu.com/#{code_name}/allpackages?format=txt.gz
returns the following line:

  mysql-server-5.5 (5.5.49-0ubuntu0.12.04.1 [amd64, i386], 5.5.22-0ubuntu1
  [armhf, powerpc]) [security] MySQL database server binaries and system
  database setup

In the previous version, extracted version number is:

  5.5.49-0ubuntu0.12.04.1 [amd64, i386], 5.5.22-0ubuntu1 [armhf, powerpc]

It isn't what upload.rb expects. we want:

  5.5.49-0ubuntu0.12.04.1

packages/ubuntu/upload.rb

@@ -85,9 +85,9 @@ def ensure_mysql_version
           case line
           when /\Amysql-server \((.+?)\)/
             @mysql_versions[code_name] = $1
-          when /\Amysql-server-5\.5 \((.+?)\)/
+          when /\Amysql-server-5\.5 \((.+?) \[/
             @mysql55_versions[code_name] = $1
-          when /\Amysql-server-5\.6 \((.+?)\)/
+          when /\Amysql-server-5\.6 \((.+?) \[/
             @mysql56_versions[code_name] = $1
           end
         end