Fix example in podman machine init man page
Fixes
@@ -54,8 +54,9 @@ Print usage statement.
## EXAMPLES
```
+$ podman machine init
$ podman machine init myvm
-$ podman machine init --device=/dev/xvdc:rw myvm
+$ podman machine init --disk-size 50
$ podman machine init --memory=1024 myvm
```
