selftests: forwarding: add shebang for sch_red.sh

stable inclusion
from stable-v5.10.146
commit 4bc4b6419e652905f71b12c70783954513d9d7f4
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I6D0VX

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=4bc4b6419e652905f71b12c70783954513d9d7f4



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[ Upstream commit 83e4b196 ]

RHEL/Fedora RPM build checks are stricter, and complain when executable
files don't have a shebang line, e.g.

*** WARNING: ./kselftests/net/forwarding/sch_red.sh is executable but has no shebang, removing executable bit

Fix it by adding shebang line.

Fixes: 6cf0291f ("selftests: forwarding: Add a RED test for SW datapath")
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Link: https://lore.kernel.org/r/20220922024453.437757-1-liuhangbin@gmail.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com>
Reviewed-by: Zheng Zengkai <zhengzengkai@huawei.com>