Use the FileOrTextIdentifier class appropriately for SVD.
Use the FileOrTextIdentifier class appropriately for SVD.

The SVD doesn't have as many restrictions as the PVD,
so make the FileOrTextIdentifier class handle both.

Signed-off-by: Chris Lalancette <281cd07d7578d97c83271fbbf2faddb83ab3791c@gmail.com>

clalancette/pyiso,clalancette/pycdlib