when we use cgsnapshot with the given controller, the result always

when we use cgsnapshot with the given controller, the result always
displays
the last mounted controller which is not specified, so fix it.

Example:

# lssubsys  -m
cpuset /cgroup/cpuset
cpu /cgroup/cpu
# lscgroup
cpu:/
cpu:/test
cpuset:/
cpuset:/test

before the patch:

# cgsnapshot -s cpu
# Configuration file generated by cgsnapshot
mount {
	cpuset = /cgroup/cpuset;
	cpu = /cgroup/cpu;
}

group test {
	cpu {
		cpu.rt_period_us="1000000";
		cpu.rt_runtime_us="0";
		cpu.shares="1024";
	}
}

group test {
	cpuset {
		cpuset.memory_spread_slab="0";
		cpuset.memory_spread_page="0";
		cpuset.memory_migrate="0";
		cpuset.sched_relax_domain_level="-1";
		cpuset.sched_load_balance="1";
		cpuset.mem_hardwall="0";
		cpuset.mem_exclusive="0";
		cpuset.cpu_exclusive="0";
		cpuset.mems="";
		cpuset.cpus="";
	}
}

after the patch:

# cgsnapshot -s cpu
# Configuration file generated by cgsnapshot
mount {
	cpuset = /cgroup/cpuset;
	cpu = /cgroup/cpu;
}

group test {
	cpu {
		cpu.rt_period_us="1000000";
		cpu.rt_runtime_us="0";
		cpu.shares="1024";
	}
}

Signed-off-by: Weng Meiling <wengmeiling.weng@huawei.com>