Fix invalid time stamp in graphite metric causes panic
Fix invalid time stamp in graphite metric causes panic

If a timestamp was larger than the max epoch value was sent via
graphite it would cause the timestamp to overflow when it was
marshaled/unmarshaled back from the raft log.  The overflow cause
the shard group to get created with the wrong timestamp which cause
a panic when writing the point.  The panic was caused because the
timestamp that were supposed to exists in a map created by MapShards
did not actually exist so a nil ShardGroup was used.

The change prevents creating the point with an invalid timestamp.  Since
graphite using a timestamp in seconds, the maximum range is known and
can be prevented.  This also adds a check for the minimum range as well.

Fixes #3785

pablolmiranda/influxdb,sudabon/influxdb,bluebreezecf/influxdb,arussellsaw/influxdb,mark-rushakoff/influxdb,CVTJNII/influxdb-tjnii,n1tr0g/influxdb,li-ang/influxdb,pkittenis/influxdb,benbjohnson/influxdb,jonseymour/influxdb,Venu4thFeb/influxdb,apriendeau/influxdb,kingland/influxdb,bluebreezecf/influxdb,mcanthony/influxdb,kingland/influxdb,runcom/influxdb,eminden/influxdb,apigee/influxdb,mnuessler/influxdb,alexiri/influxdb,joaopedrotaveira/influxdb,cnelissen/influxdb,apriendeau/influxdb,linearb/influxdb,apriendeau/influxdb,arussellsaw/influxdb,apigee/influxdb,kingland/influxdb,eminden/influxdb,trigrass2/influxdb,mnuessler/influxdb,apriendeau/influxdb,linearb/influxdb,mcanthony/influxdb,roobert/influxdb,chenziliang/influxdb,apigee/influxdb,alexiri/influxdb,influxdata/influxdb,mcanthony/influxdb,Tony133/influxdb,bluebreezecf/influxdb,toorop/influxdb,GrimDerp/influxdb,Mindera/influxdb,m4ce/influxdb,arussellsaw/influxdb,opavader/influxdb,joaopedrotaveira/influxdb,linearb/influxdb,otoolep/influxdb,mre/influxdb,pablolmiranda/influxdb,toorop/influxdb,daachi/influxdb,lenko-d/influxdb,cnelissen/influxdb,lgpeterson/influxdb,n1tr0g/influxdb,nooproblem/influxdb,cnelissen/influxdb,kingland/influxdb,influxdb/influxdb,runcom/influxdb,runcom/influxdb,alexiri/influxdb,mvadu/influxdb,DanielMorsing/influxdb,pablolmiranda/influxdb,mvadu/influxdb,m4ce/influxdb,imcom/influxdb,tuxmonteiro/influxdb,trigrass2/influxdb,lgpeterson/influxdb,jgeiger/influxdb,lgpeterson/influxdb,GrimDerp/influxdb,josephcopenhaver/influxdb,GrimDerp/influxdb,mre/influxdb,runner-mei/influxdb,imcom/influxdb,runcom/influxdb,Ancillas/influxdb,mark-rushakoff/influxdb,nckturner/influxdb,li-ang/influxdb,nooproblem/influxdb,tommymei/influxdb,roobert/influxdb,roobert/influxdb,mvadu/influxdb,Mindera/influxdb,jgeiger/influxdb,nickrobinson/influxdb,DanielMorsing/influxdb,n1tr0g/influxdb,otoolep/influxdb,mvadu/influxdb,samaitra/influxdb,vladlopes/influxdb,alexiri/influxdb,archsaber/influxdb,pkittenis/influxdb,mcanthony/influxdb,CVTJNII/influxdb-tjnii,DanielMorsing/influxdb,samaitra/influxdb,lenko-d/influxdb,daachi/influxdb,vladlopes/influxdb,m4ce/influxdb,runner-mei/influxdb,daachi/influxdb,otoolep/influxdb,CVTJNII/influxdb-tjnii,lenko-d/influxdb,wxdublin/influxdb,lgpeterson/influxdb,nickrobinson/influxdb,josephcopenhaver/influxdb,mcanthony/influxdb,runner-mei/influxdb,arussellsaw/influxdb,archsaber/influxdb,mre/influxdb,mvadu/influxdb,mark-rushakoff/influxdb,jgeiger/influxdb,linearb/influxdb,GrimDerp/influxdb,runcom/influxdb,chenziliang/influxdb,mre/influxdb,chenziliang/influxdb,nckturner/influxdb,arussellsaw/influxdb,sudabon/influxdb,mark-rushakoff/influxdb,Ancillas/influxdb,mmaul/influxdb,tuxmonteiro/influxdb,joaopedrotaveira/influxdb,mnuessler/influxdb,paulstuart/influxdb,lenko-d/influxdb,tuxmonteiro/influxdb,paulstuart/influxdb,benbjohnson/influxdb,archsaber/influxdb,cnelissen/influxdb,pkittenis/influxdb,cnelissen/influxdb,jonseymour/influxdb,CVTJNII/influxdb-tjnii,imcom/influxdb,tommymei/influxdb,nooproblem/influxdb,Tony133/influxdb,apigee/influxdb,toorop/influxdb,joaopedrotaveira/influxdb,paulstuart/influxdb,chenziliang/influxdb,eminden/influxdb,archsaber/influxdb,Ancillas/influxdb,daachi/influxdb,alexiri/influxdb,DanielMorsing/influxdb,josephcopenhaver/influxdb,Ancillas/influxdb,mmaul/influxdb,Mindera/influxdb,pablolmiranda/influxdb,wxdublin/influxdb,trigrass2/influxdb,Mindera/influxdb,runner-mei/influxdb,jipperinbham/influxdb,jonseymour/influxdb,nickrobinson/influxdb,lenko-d/influxdb,apigee/influxdb,nickrobinson/influxdb,GrimDerp/influxdb,sudabon/influxdb,jipperinbham/influxdb,mre/influxdb,josephcopenhaver/influxdb,tommymei/influxdb,influxdb/influxdb,opavader/influxdb,vladlopes/influxdb,opavader/influxdb,jipperinbham/influxdb,influxdb/influxdb,Ancillas/influxdb,samaitra/influxdb,sudabon/influxdb,eminden/influxdb,wxdublin/influxdb,pablolmiranda/influxdb,toorop/influxdb,lgpeterson/influxdb,kingland/influxdb,samaitra/influxdb,nckturner/influxdb,nckturner/influxdb,bluebreezecf/influxdb,roobert/influxdb,wxdublin/influxdb,tommymei/influxdb,tuxmonteiro/influxdb,CVTJNII/influxdb-tjnii,Tony133/influxdb,mmaul/influxdb,Venu4thFeb/influxdb,otoolep/influxdb,mvadu/influxdb,mnuessler/influxdb,jonseymour/influxdb,otoolep/influxdb,m4ce/influxdb,paulstuart/influxdb,trigrass2/influxdb,n1tr0g/influxdb,opavader/influxdb,imcom/influxdb,daachi/influxdb,wxdublin/influxdb,apriendeau/influxdb,CVTJNII/influxdb-tjnii,benbjohnson/influxdb,samaitra/influxdb,samaitra/influxdb,nooproblem/influxdb,jipperinbham/influxdb,sudabon/influxdb,Venu4thFeb/influxdb,jgeiger/influxdb,opavader/influxdb,mmaul/influxdb,pkittenis/influxdb,influxdb/influxdb,jipperinbham/influxdb,tuxmonteiro/influxdb,pkittenis/influxdb,imcom/influxdb,m4ce/influxdb,jonseymour/influxdb,joaopedrotaveira/influxdb,Tony133/influxdb,vladlopes/influxdb,jgeiger/influxdb,Mindera/influxdb,influxdata/influxdb,m4ce/influxdb,Mindera/influxdb,mnuessler/influxdb,nooproblem/influxdb,otoolep/influxdb,roobert/influxdb,influxdb/influxdb,trigrass2/i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