GVfs macro names

[Jürg Billeter <j bitron ch>]

Hi Alex,

I've noticed that you've committed G_TYPE_VFS_xxx -> G_VFS_TYPE_xxx
renaming to git, i.e. G_VFS (resp. GVfs) is the namespace now.

The type checking macros are still G_IS_VFS_xxx, that doesn't seem to be
consistent with other libraries, AFAIK. Shouldn't it be G_VFS_IS_xxx?

Regards,

Jürg