removed provider definition from gradle (only needed within vagrant)

CHANGELOG.md

 Upcoming version:
 -----------------
+  - removed provider definition from gradle (only needed within vagrant) (Nikolaus Krismer)
   - fixed syntax error in Vagrantfile (Nikolaus Krismer)
   - preparations to use libvirt on dbis-ci test system (Nikolaus Krismer)
   - preparations to use libvirt on dbis-ci test system (Nikolaus Krismer)

build.gradle

@@ -87,10 +87,6 @@ scmversion {
 	releaseTagPattern = 'v([0-9.]*)'
 }
 
-vagrant {
-	provider = 'virtualbox'
-}
-
 vagrantDestroy.doFirst {
 	if (!vagrantDir.isDirectory()) {
 		throw new StopExecutionException()