[infra] Remove unused flags in gen_tasks.go.

Bug: skia:6637
No-Try: true
Change-Id: Ic2fba996a0fead3cfac61e86874cca13271bb595
Reviewed-on: https://skia-review.googlesource.com/19805
Reviewed-by: Eric Boren <borenet@google.com>
Commit-Queue: Ben Wagner <benjaminwagner@google.com>
1 file changed