Fixed manipulation with global libraries in some weird cases

Change-Id: Ife4ca8c8d2c42820dc74246e6ad2a76d33047d46
diff --git a/_states/jenkins_lib.py b/_states/jenkins_lib.py
index 6492623..10ef75f 100644
--- a/_states/jenkins_lib.py
+++ b/_states/jenkins_lib.py
@@ -28,8 +28,12 @@
     LibraryConfiguration library = new LibraryConfiguration("{lib_name}", retriever)
     library.setDefaultVersion("{branch}")
     library.setImplicit({implicit})
-    globalLibsDesc.get().getLibraries().removeIf{{ it.name.equals("{lib_name}")}}
-    globalLibsDesc.get().getLibraries().add(library)
+    if(globalLibsDesc.get().getLibraries().isEmpty()){{
+      globalLibsDesc.get().setLibraries([library])
+    }}else{{
+      globalLibsDesc.get().getLibraries().removeIf{{ it.name.equals("{lib_name}")}}
+      globalLibsDesc.get().getLibraries().add(library)
+    }}
     print("SUCCESS")
 }}
 """ # noqa