Searching for rails executable correctly

 * Current logic of finding Rails executable in parent directory is
   not returning full path of executable if it is found in one of the
   parent directories
 * To compensate for this, we have to call exec_app_rails recursively
   until the executable is found or we cant do 'chdir' anymore
 * This solution finds the correct executable path from parent
   directory(s) recursively
Merge pull request #10157 from prathamesh-sonpatki/app_loader

Searching for rails executable correctly