fix check if blob is uninteresting when inserting tree to packbuilder Blobs that have been marked as uninteresting should not be inserted into packbuilder when inserting a tree. The check as to whether a blob was uninteresting looked at the status for the tree itself instead of the blob. This could cause significantly larger packfiles. (cherry picked from commit b36cc7a4013a47856dade4226edc657906b82431)