Fix systemic spelling error in source
Fix systemic spelling error in source

"restor_spec" is now "restore_spec".

nagual13/wal-e,fdr/wal-e,RichardKnop/wal-e,equa/wal-e,x86Labs/wal-e,intoximeters/wal-e,ajmarks/wal-e,heroku/wal-e,modulexcite/wal-e,wal-e/wal-e,tenstartups/wal-e,ArtemZ/wal-e,DataDog/wal-e