Abrt: toctou race condition in abrt-dbus setelement allows arbitrary file writes to dump directories

A time-of-check time-of-use (TOCTOU) race condition was found in the abrt-dbus D-Bus service's SetElement method. Between dump directory creation and post-create event execution, any local user can call SetElement to write arbitrary text files into the root-owned dump directory, bypassing package validation and allowing crashes of unpackaged binaries to survive post-create processing.