Rename 'GenerateTapName' to 'GenerateKvmTapName'
Rename 'GenerateTapName' to 'GenerateKvmTapName'

This is an intermediary step before extracting most of the body of
'GenerateTapName' to a separate function that can be reused by the Xen
hypervisor as well.

Signed-off-by: Jose A. Lopes <0fb9c4f8511df4ec2ae28af879e9d462f6218a2c@google.com>
Reviewed-by: Hrvoje Ribicic <be5828fca31f89218048bec4189e30a581aa65da@google.com>

apyrgio/ganeti,ganeti/ganeti,ganeti/ganeti,onponomarev/ganeti,ganeti-github-testing/ganeti-test-1,leshchevds/ganeti,yiannist/ganeti,andir/ganeti,dimara/ganeti,andir/ganeti,ganeti-github-testing/ganeti-test-1,bitemyapp/ganeti,yiannist/ganeti,mbakke/ganeti,apyrgio/ganeti,yiannist/ganeti,leshchevds/ganeti,bitemyapp/ganeti,grnet/snf-ganeti,mbakke/ganeti,andir/ganeti,leshchevds/ganeti,dimara/ganeti,mbakke/ganeti,grnet/snf-ganeti,ganeti/ganeti,onponomarev/ganeti