Do not fail build, if publishing information are not given.

build.gradle

@@ -164,8 +164,8 @@ publishing {
             name 'nexus'
             url "http://172.22.1.152:8081/repository/" + (project.hasProperty('asSnapshot') ? "maven-snapshots" : "maven-releases/")
             credentials {
-                username project.repoUser
-                password project.repoPassword
+                username project.ext.properties.repoUser
+                password project.ext.properties.repoPassword
             }
         }
     }