Don't error when an @import is terminated by the end of the block
Don't error when an @import is terminated by the end of the block

Semicolons are optional for the final declaration of a block. In this
case the `}` acts as the declaration's terminator. This was not being
handling correctly with `@import`s because they can be followed by a
media query.

Fixes #2233
Spec sass/sass-spec#982

am11/libsass,am11/libsass,am11/libsass,am11/libsass,am11/libsass