Remove typo from RAPI documentation
Remove typo from RAPI documentation

"be used instead." was repeated twice.

Signed-off-by: Michele Tartara <05f7077a2c6cbbdc4af4ba42e3ef89a0df846179@google.com>
Reviewed-by: Klaus Aehlig <4ce51de36d9068cd7db2eec1151e0f3f95419008@google.com>

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