Don't use len(errorsChan) as the number of errors to expect
Don't use len(errorsChan) as the number of errors to expect

The length of a buffered channel is the number of elements waiting in it.
We can have a race condition by which some of the goroutines have not yet sent
their results, and thus this len() is lower than 2*len(self.externalSinks),
and we just don't grab all the errors.

This situation also results in Store() returning before it's finished doing
its thing.

burmanm/heapster,whuwxl/heapster,apeeyush/heapster,aegixx/heapster,aegixx/heapster,skytap/heapster,jfoy/heapster,relh/heapster,apeeyush/heapster,relh/heapster,vishh/heapster-1,wulonghui/heapster,huangyuqi/heapster,burmanm/heapster,mwringe/heapster,ravihansa3000/heapster,huangyuqi/heapster,shilpamayanna/heapster,saiwl/heapster,piosz/heapster,mwringe/heapster,krzyzacy/heapster,Stackdriver/heapster,mwielgus/heapster,andyxning/heapster,AlmogBaku/heapster,wulonghui/heapster,jackzampolin/heapster,krzyzacy/heapster,saiwl/heapster,andyxning/heapster,dalanlan/heapster,adfin/statster,mwielgus/heapster,titilambert/heapster,afein/heapster,liubog2008/heapster,skytap/heapster,fzu-huang/heapster,digideskio/heapster,thucatebay/heapster,naxhh/heapster,vicki-c/heapster,taimir/heapster,liubog2008/heapster,jfoy/heapster,johanneswuerbach/heapster,mdshuai/heapster,ravihansa3000/heapster,shilpamayanna/heapster,naxhh/heapster,dalanlan/heapster,a-robinson/heapster,vicki-c/heapster,luxas/heapster,vishh/heapster-1,bluebreezecf/heapster,Huawei-PaaS/heapster,Stackdriver/heapster,nlamirault/heapster,bluebreezecf/heapster,fzu-huang/heapster,piosz/heapster,Huawei-PaaS/heapster,luxas/heapster,AlmogBaku/heapster,liuhewei/heapster,liuhewei/heapster,jackzampolin/heapster,whuwxl/heapster,afein/heapster,nlamirault/heapster,bruceauyeung/heapster,mdshuai/heapster,taimir/heapster,titilambert/heapster,johanneswuerbach/heapster,thucatebay/heapster,digideskio/heapster,bruceauyeung/heapster,adfin/statster,a-robinson/heapster