Fix specification of TIDiskParams
Fix specification of TIDiskParams

Commit 580b1fdd incorrectly assumes that disk parameters are
just the standard ones, whereas the man page explicitly states
that additional parameters can be passed as well, if they make
sense for the chosen storage type. Fix this.

Signed-off-by: Klaus Aehlig <4ce51de36d9068cd7db2eec1151e0f3f95419008@google.com>
Reviewed-by: Petr Pudlak <pudlak@google.com>

Cherry-picked from b26a275a0. Fixes issue 779.

Signed-off-by: Klaus Aehlig <4ce51de36d9068cd7db2eec1151e0f3f95419008@google.com>
Reviewed-by: Hrvoje Ribicic <be5828fca31f89218048bec4189e30a581aa65da@google.com>

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