kotlin-maven-plugin: Don't print warning on no resources to compile

(cherry picked from commit 364b89099d6528ee01955ce32fd42bf8d5e7f8cc)

libraries/tools/kotlin-maven-plugin/src/main/java/org/jetbrains/kotlin/maven/KotlinCompileMojoBase.java

@@ -203,7 +203,7 @@ public abstract class KotlinCompileMojoBase<A extends CommonCompilerArguments> e
                 " (JRE " + System.getProperty("java.runtime.version") + ")");
 
         if (!hasKotlinFilesInSources()) {
-            getLog().warn("No sources found skipping Kotlin compile");
+            getLog().info("No sources found skipping Kotlin compile");
             return;
         }