Fix a build error

build.gradle

@@ -87,10 +87,12 @@ task buildResources {
     doLast {
         File to = new File("${buildDir}/classes/java/main/META-INF/services/javax.annotation.processing.Processor")
         to.parentFile.mkdirs()
+        if (!to.exists()) {
             to.createNewFile()
             to.append("de.steamwar.linkage.LinkageProcessor\n")
         }
     }
+}
 classes.finalizedBy(buildResources)
 
 task buildProject {