Fix bug related to repeated sudo prompt due to set_override calls (#531)

set_override method is now called only if force flag is invoked.

Here are the specific code changes made:

In auto_cpufreq/core.py:
- Line 96: Removed the root_check call from the set_override function.
           This was intended to be done to comply with code template,
           i.e., to use root_check in the main file.

In bin/auto-cpufreq:
- Line 45: Added a root_check call before calling set_override in main program.
           Also, set_override is only called if force option is invoked, saving
           us from precious extra overheads.

Fixes #530

auto_cpufreq/core.py

@@ -96,7 +96,6 @@ def get_override():
         return "default"
 
 def set_override(override):
-    root_check() # Calling root_check inside if and elif might be too verbose and is susceptible to bugs in future
     if override in ["powersave", "performance"]:
         with open(governor_override_state, "wb") as store:
             pickle.dump(override, store)

bin/auto-cpufreq

@@ -45,7 +45,8 @@ def main(config, daemon, debug, install, remove, live, log, monitor, stats, vers
     # set governor override unless None or invalid
     if force is not None:
         not_running_daemon_check()
-    set_override(force)
+        root_check() # Calling root_check before set_override as it will require sudo access
+        set_override(force) # Calling set override, only if force has some values
 
     if len(sys.argv) == 1: