s3 create-tarball.sh: Remove dashes in git commands.

s3 create-tarball.sh: Remove dashes in git commands.

Newer git versions (e.g. 1.6.0.2) do not provide the 'git-' commands
any longer.

Karolin
(cherry picked from commit 0cba859f12177aaf3ef2d96663f0a51f61c24d56)
(cherry picked from commit 3d64e67de2b50f7b781aa3f5ad13ec8e866d4333)
(cherry picked from commit aa41a80969bd413d5922c602c7309bd8c05f3181)
(cherry picked from commit 0b4dd0cb1f81126344a6fe3304b46f880089718d)
(cherry picked from commit 4d988d0c9f22dda706ee1802985830ce4999f4d5)
(cherry picked from commit b0f66f65e4d7cf0d70708783e5486fe3e1e5e8e8)