facebook/rocksdb — pull request #264 by huahang (2014-09-04 13:36:57+00:00)
Title: fix a compile warning

Class HistogramImpl has virtual functions and thus should have a virtual destructor. Otherwise, a compile error will be triggered by this flag

-Werror=non-virtual-dtor

error: 'class rocksdb::HistogramImpl' has virtual functions and accessible non-virtual destructor [-Werror=non-virtual-dtor]