Test Fix: Nil error handling

In TestExternalUnmount, the Mount function is called which returns an
error which can be nil. The error type is then used in a comparison
where Error() is called on it. If the error is nil, this results in a
panic.

Added a if err != nil {} guard to make sure that Error() is not called
if the value is nil
 On branch go-test-fix
 Changes to be committed:
	modified:   fuse/node/mount_test.go
License: MIT
Signed-off-by: Chris Buesser <christopher.buesser@gmail.com>

fuse/node/mount_test.go

@@ -64,9 +64,12 @@ func TestExternalUnmount(t *testing.T) {
 	mkdir(t, ipnsDir)
 
 	err = Mount(node, ipfsDir, ipnsDir)
-	if strings.Contains(err.Error(), "unable to check fuse version") || err == fuse.ErrOSXFUSENotFound {
-		t.Skip(err)
+	if err != nil {
+		if strings.Contains(err.Error(), "unable to check fuse version") || err == fuse.ErrOSXFUSENotFound {
+			t.Skip(err)
+		}
 	}
+
 	if err != nil {
 		t.Fatalf("error mounting: %v", err)
 	}