small spice_strdup optimization
small spice_strdup optimization

avoid to compute the string length twice and use memcpy instead of
strcpy which is faster not having to check for terminator.

Signed-off-by: Frediano Ziglio <55d48b080b2e443e395cde84d2c83b135a4ff48e@redhat.com>
Acked-by: Jonathon Jongsma <c7254805a17bd5c41e24c3a278fcbf3afcdfb0fa@redhat.com>

fgouget/spice-common,SPICE/spice-common,fgouget/spice-common,SPICE/spice-common,fgouget/spice-common,SPICE/spice-common,fgouget/spice-common