Revert "tools:releasetools:Use timestamp from build.prop while building system.img"

  build_command = []

  fs_type = prop_dict.get("fs_type", "")

  run_fsck = False

  is_verity_partition = "verity_block_device" in prop_dict

  verity_supported = prop_dict.get("verity") == "true"

  # adjust the partition size to make room for the hashes if this is to be verified

      build_command.extend(["-j", prop_dict["journal_size"]])

    if "timestamp" in prop_dict:

      build_command.extend(["-T", str(prop_dict["timestamp"])])

    else:

      #Timestamp not provided in property_dict.

      #Lets try to find the build.prop file and get the timestamp from there

      #instead

      path = in_dir + "/build.prop"

      if os.path.exists(path):

        with open(path) as f:

          lines = f.readlines()

          for line in lines:

            line = line.strip()

            if line.startswith("ro.build.date.utc"):

              name, value = line.split("=", 1)

              print "read ro.build.date.utc from build.prop as ", value

              build_command.extend(["-T", value])

      else:

        print "unable to open build.prop file..Image will be built using system time"

    if fs_config is not None:

      build_command.extend(["-C", fs_config])

    if block_list is not None: