Even though SIMPLE_PATH_RE is used with re.match (which anchors the
match implictly to the beginning of the string) it also needs an
end-of-string anchor in order to match the full path token.

Otherwise, the match would succeed incorrectly for $ and : characters
contained in the path, for example if the path starts with C:/ or E:/.

Signed-off-by: Yonggang Luo <luoyonggang@gmail.com>
Tested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>