QA:Testcase tuna

Description

this case test the functions of tuna, use it to change priority of process

How to test

1. get the pid of one process, watchdog/0 for example

 pgrep "watchdog/0"

2. get the status of the process, and get the priority of the process

 chrt -p $(pgrep "watchdog/0")
 output: 
 pid 17's current scheduling policy: SCHED_FIFO
 pid 17's current scheduling priority: 99

3. change priority for the process with tuna

 tuna -t  "watchdog/0" -p 97

4. check if the operation takes effect

 chrt -p $(pgrep "watchdog/0")
 output should be: 
 pid 17's current scheduling policy: SCHED_FIFO
 pid 17's current scheduling priority: 97

Expected Results

1. tuna can change priority of the process successfully