explicitly check whether destFile exists in <copy file="..."/>

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@273444 13f79535-47bb-0310-9956-ffa450edef68

src/main/org/apache/tools/ant/taskdefs/Copy.java

@@ -329,6 +329,7 @@ public class Copy extends Task {
                     }
 
                     if (forceOverwrite ||
+                        !destFile.exists() ||
                         (file.lastModified() > destFile.lastModified())) {
                         fileCopyMap.put(file.getAbsolutePath(),
                                         destFile.getAbsolutePath());