osdict: Add back compat 'virtio26' entry

We used to have that in the old osdict. Map it to fedora10 which gives
virtio net/block but nothing else, which matches the old behavior.

tests/misc.py

@@ -125,7 +125,7 @@ class TestMisc(unittest.TestCase):
         from virtinst import osdict
         aliases = getattr(osdict, "_aliases")
 
-        if len(aliases) != 39:
+        if len(aliases) != 40:
             raise AssertionError(_("osdict._aliases changed size. It "
                 "should never be extended, since it is only for back "
                 "compat with pre-libosinfo osdict."))

virtinst/osdict.py

@@ -69,6 +69,7 @@ _aliases = {
     "linux" : "generic",
     "windows" : "winxp",
     "solaris" : "solaris10",
+    "virtio26": "fedora10",
 }
 _SENTINEL = -1234
 _allvariants = {}