Puleglot libupnp 1.18 - #448

…mule-project#448)

17-shared-priority-patch renamed the first shared file to a fixed
"renamed-by-test.dat" and never restored the original name. Against the
persistent daemon the suite targets, that (a) clobbered a real shared
file and (b) made the next run fail: renaming a file to its existing
name is a no-op amuled rejects with non-200, so the second run's
"PATCH name (rename) -> 200" bounced.

Capture the original name alongside the saved priority, rename to a name
guaranteed different from it (verifying the change lands with an
immediate GET), run the traversal/empty-name negative checks, then
restore the original name. jq builds the request body so odd characters
in a real filename are escaped. The file is now left exactly as found.