Move build status to top and correct branch. [ci skip]

Author: christophercurrie

README.md

@@ -1,3 +1,5 @@
+[![Build Status](https://travis-ci.org/FasterXML/jackson-module-scala.svg?branch=master)](https://travis-ci.org/FasterXML/jackson-module-scala)
+
 # IMPORTANT
 
 Version 2.6.0 of this module has been released incorrectly. Please refrain
@@ -37,8 +39,6 @@ issue, but since it's possible to turn this off, be aware that the current
 version will throw an exception if it cannot find the constructor parameter
 names. Future versions may permit configuration to suppress this exception.
 
-[![Build Status](https://travis-ci.org/FasterXML/jackson-module-scala.svg?branch=2.4)](https://travis-ci.org/FasterXML/jackson-module-scala)
-
 # Usage
 
 To use the Scala Module in Jackson, simply register it with the