selftests: forwarding: lib: quote the sysctl values

stable inclusion
from stable-v5.10.168
commit 3914b71dad5a5527819f82f1d085f0087583bdeb
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7URR4

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3914b71dad5a5527819f82f1d085f0087583bdeb



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[ Upstream commit 3a082086 ]

When set/restore sysctl value, we should quote the value as some keys
may have multi values, e.g. net.ipv4.ping_group_range

Fixes: f5ae5778 ("selftests: forwarding: lib: Add sysctl_set(), sysctl_restore()")
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Link: https://lore.kernel.org/r/20230208032110.879205-1-liuhangbin@gmail.com


Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: zhaoxiaoqiang11 <zhaoxiaoqiang11@jd.com>