Summary:
Overload RepairDB to take vector-of-ColumnFamilyDescriptor, which tells
us CF name + options. Also takes a ColumnFamilyOptions for unspecified column
families encountered during the repair.

One potentially confusing thing is that we store options in the constructor and
don't invoke AddColumnFamily() until discovering the CF in ScanTable. This is
because we don't know the CF ID until we find a table belonging to that CF.

Depends on D59781.

Test Plan:
  $ ./repair_test

Reviewers: yhchiang, IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D59853