pxar: fix anchored exclusion at archive root

There is no leading slash in an entry's full_path, causing an anchored
exclude at the root level to fail, e.g. having "/name" as the content of the
file archive/root/.pxarexclude didn't match the file archive/root/name

Fix this by prepending a leading slash before matching.

Signed-off-by: Fabian Ebner <f.ebner@proxmox.com>
Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>

src/pxar/create.rs

@@ -443,9 +443,10 @@ impl<'a, 'b> Archiver<'a, 'b> {
                 Err(err) => bail!("stat failed on {:?}: {}", full_path, err),
             };
 
+            let match_path = PathBuf::from("/").join(full_path.clone());
             if self
                 .patterns
-                .matches(full_path.as_os_str().as_bytes(), Some(stat.st_mode as u32))
+                .matches(match_path.as_os_str().as_bytes(), Some(stat.st_mode as u32))
                 == Some(MatchType::Exclude)
             {
                 continue;