scripts: Avoid warning from mkdosfs command

Fix lowercase label to avoid "mkfs.fat: Warning: lowercase labels
might not work properly on some systems".

Signed-off-by: Ravi kumar Veeramally <ravikumar.veeramally@intel.com>

test_infra/src/lib.rs

@@ -301,7 +301,7 @@ impl DiskConfig for UbuntuDiskConfig {
             .expect("Expected writing out network-config to succeed");
 
         std::process::Command::new("mkdosfs")
-            .args(["-n", "cidata"])
+            .args(["-n", "CIDATA"])
             .args(["-C", cloudinit_file_path.as_str()])
             .arg("8192")
             .output()