[BuildMonitor] change the method of getting the build_project_id

[BuildMonitor] change the method of getting the build_project_id

1. change the method of getting the build_project_id
   to prevent getting the wrong build_project_id
   when there are too many jenkins jobs including the 'BUILD-MONITOR' job simultaneously

  [CHAGNED]
  1-1. # get last_bpid_of_build_snapshot
  1-2. # get post_build_project_id
  1-3. # use the prev last_bpid if there is no post_build_project_id (for manual trigger)

2. the query_data in some functions should be changed from 'project' to 'bm_snapshot_name'
   bcz of the above solution

3. clean up some codes
  3-1. replace the query_data from build_id to bm_snapshot_name
       to clarify the meaning of the snapshot name
  3-2. remove unused code

Change-Id: Ia659e8461b6ed0a0c2ad87e178bc96e12c3c1707
Signed-off-by: SungHun Hwang <sh0924.hwang@samsung.com>