Fix merge 8e09e801 that resulted in duplicated code
Fix merge 8e09e801 that resulted in duplicated code

A fragment in LUInstanceCreate.CheckPrereq() removed in commit ba147ff8 was
reintroduced in merge 8e09e801 due to a change in df28c49b.

Signed-off-by: Bernardo Dal Seno <dcdd79c5479cb9d1329ec01d126f02cb045aa103@google.com>
Reviewed-by: Guido Trotter <f62ca4d5358bdaeef0e50e57f9f7e231de63727e@google.com>

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