[colord] xrandr id unstable

[Sanford Rockowitz]

I just stumbled across the following issue because it tripped up one of 
my utility programs for managing color profiles.   Perhaps its a known 
anomaly that does not pose a problem for colord, but it surprised me.

By xrandr id I mean the identifier that looks like:
   xrandr-Dell-DELL P2411H-F8NDP11G119U

My understanding of this identifier is that it's constructed by taking 
the model and serial number directly from the EDID.  The manufacturer 
field is obtained by looking up the manufacturer code from the EDID in 
the pnp.ids file.    This value is stored in the Mapping Device ID 
metatag field of the profile.

The problem is that the pnp.ids field can vary from installation to 
installation (and dispcalGUI even has its own private copy), so if you 
copy a profile from one installation to another, the stored metatag 
value may not match the value calculated from the EDID.  As a result, 
comparisons that should match will fail.   For example, on my Fedora 18 
installation, manufacturer code 'DEL' maps to manufacturer name 'Dell', 
but on my Fedora 19 installation (created by cloning the Fedora 18 
installation and upgrading), it maps to 'Dell Inc.'.

Sanford