cbimport sample data not restored if sample bucket given a different name

cbimport sample will fail if a different bucket name is given to the one expected in the queries. This will cause non of the data to be imported.

To avoid this in the sample format instead of having the bucket in the queries it will have the string @BUCKET_NAME@ then the sample importer will replace this string with the target bucket. We do not have to worry about N1QL injection as the bucket name will always be surronded by `` which means anything there is treated as a literal and as the bucket has to exist it means the name can only contain:

A bucket name can only contain characters in the ranges of A-Z, a-z, and 0-9; with the addition of the underscore, period, dash and percent characters; and can be no more than 100 characters in length.