Fix a few unclear sentences in gnt-cluster(8)
Fix a few unclear sentences in gnt-cluster(8)

The renew-crypto entry had a few obscure sentences. Improve it by
rephrasing it.

Signed-off-by: Guido Trotter <f62ca4d5358bdaeef0e50e57f9f7e231de63727e@google.com>
Reviewed-by: Klaus Aehlig <4ce51de36d9068cd7db2eec1151e0f3f95419008@google.com>

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