Refactor Backup#import into multiple methods.
Refactor Backup#import into multiple methods.

hauledev/bookyt,huerlisi/bookyt,wtag/bookyt,hauledev/bookyt,gaapt/bookyt,gaapt/bookyt,hauledev/bookyt,gaapt/bookyt,silvermind/bookyt,hauledev/bookyt,silvermind/bookyt,wtag/bookyt,wtag/bookyt,silvermind/bookyt,silvermind/bookyt,huerlisi/bookyt,xuewenfei/bookyt,xuewenfei/bookyt,xuewenfei/bookyt,gaapt/bookyt,huerlisi/bookyt