[UIMA-6307] Centralize Jenkins pipelines

- Fixed agent label setting (hopefully)
diff --git a/vars/defaultPipeline.groovy b/vars/defaultPipeline.groovy
index 8407639..44f9cb4 100644
--- a/vars/defaultPipeline.groovy
+++ b/vars/defaultPipeline.groovy
@@ -21,7 +21,9 @@
   def config = createConfiguration(body)
     
   pipeline {
-    agent config.agentLabel
+    agent {
+      label config.agentLabel
+    }
   
     tools {
       maven config.maven