libs: Resolve unused import warning

I'm not sure why we aren't catching this elsewhere, but
when running checks I saw the unused
import warning, so thought I would fix it

Signed-off-by: stevenhorsman <steven@uk.ibm.com>

src/libs/kata-sys-util/src/pcilibs/pci_manager.rs

@@ -179,7 +179,6 @@ mod tests {
     use super::*;
     use std::fs;
     use std::io::Write;
-    use std::path::PathBuf;
 
     // domain number
     const TEST_PCI_DEV_DOMAIN: &str = "0000";