Set joelhockey as OWNER for crostini_share_path*

Change-Id: I42a6b49cc52dfc2a085c1b6ffad6b72ab6e34a11
Reviewed-on: https://chromium-review.googlesource.com/c/1335053Reviewed-by: Nicholas Verne <nverne@chromium.org>
Commit-Queue: Joel Hockey <joelhockey@chromium.org>
Cr-Commit-Position: refs/heads/master@{#607903}

chrome/browser/chromeos/crostini/OWNERS

 benwells@chromium.org
 nverne@chromium.org
 timloh@chromium.org
+
+per-file crostini_share_path*=joelhockey@chromium.org