appengine/cmd/aedeploy: follow symlinks to folders when copying tree

Fixes #7.

Change-Id: I5b61b18dcda0d32bef9e7ef9366371b4ac39ea29
diff --git a/cmd/aedeploy/aedeploy.go b/cmd/aedeploy/aedeploy.go
index 5cfb3c1..4f44a11 100644
--- a/cmd/aedeploy/aedeploy.go
+++ b/cmd/aedeploy/aedeploy.go
@@ -203,6 +203,11 @@
 			continue
 		}
 		s := filepath.Join(srcDir, n)
+		if entry.Mode()&os.ModeSymlink == os.ModeSymlink {
+			if entry, err = os.Stat(s); err != nil {
+				return fmt.Errorf("unable to stat %v: %v", s, err)
+			}
+		}
 		d := filepath.Join(dstDir, n)
 		if entry.IsDir() {
 			if err := copyTree(dstRoot, d, s); err != nil {