Deprecate PosixException in favor of IOException (#6345)

core/src/main/java/hudson/FilePath.java

@@ -42,7 +42,6 @@ import hudson.model.AbstractProject;
 import hudson.model.Computer;
 import hudson.model.Item;
 import hudson.model.TaskListener;
-import hudson.os.PosixException;
 import hudson.remoting.Callable;
 import hudson.remoting.Channel;
 import hudson.remoting.DelegatingCallable;
@@ -1985,7 +1984,7 @@ public final class FilePath implements SerializableOnlyOverRemoting {
      * @since 1.311
      * @see #chmod(int)
      */
-    public int mode() throws IOException, InterruptedException, PosixException {
+    public int mode() throws IOException, InterruptedException {
         if (!isUnix())   return -1;
         return act(new Mode());
     }