Fix: Only delete Multipart tmp files after rules have run

test/test-cases/data/inspectFile-abcdef.lua

@@ -0,0 +1,10 @@
+#!/usr/bin/lua
+
+function main(filename)
+    local file = io.open(filename, 'r')
+    local chunk = file:read(1024)
+    local ret = string.match(chunk, 'abcdef')
+    io.close(file)
+
+    return ret
+end