So, this noise was being so annoying and last weekend I decided to open up brake myself.  (In past I have replaced brake rotors, pads on my old & friends car) 
  
I opened up tire & disassembled all the brake parts, Cleaned callipers & brake parks with break cleaner, there was rust on the callipers where break pads move. After cleaning all the rust I applied grease on moving parts (I shouldnt have applied that, but I didnt know what was actual paste kind of thing I should apply). Assembled the parts again and wowwwwwwww.... 
The annoying noise was gone and it drives like brand new again.. 
  
hope it will help someone. 
  
Thank you.