releasetools: Use int value of FIXED_FILE_TIMESTAMP.

Otherwise it gives a floating-point value (i.e. 1230768000.0). e2fsdroid
(i.e. the user of the value) didn't complain though, because it calls
strtoul(3) without checking endptr.

Bug: 80600931
Test: `m dist` with aosp_taimen-userdebug, check the build log.
Change-Id: I7467a60c947134b42f079c7a57fb8a9a9d4277da
diff --git a/tools/releasetools/add_img_to_target_files.py b/tools/releasetools/add_img_to_target_files.py
index 0c9b195..e47c038 100755
--- a/tools/releasetools/add_img_to_target_files.py
+++ b/tools/releasetools/add_img_to_target_files.py
@@ -77,8 +77,9 @@
                             'odm')
 # Use a fixed timestamp (01/01/2009 00:00:00 UTC) for files when packaging
 # images. (b/24377993, b/80600931)
-FIXED_FILE_TIMESTAMP = (datetime.datetime(2009, 1, 1, 0, 0, 0, 0, None)
-                        - datetime.datetime.utcfromtimestamp(0)).total_seconds()
+FIXED_FILE_TIMESTAMP = int((
+    datetime.datetime(2009, 1, 1, 0, 0, 0, 0, None) -
+    datetime.datetime.utcfromtimestamp(0)).total_seconds())
 
 
 class OutputFile(object):
@@ -98,6 +99,7 @@
     if self._output_zip:
       common.ZipWrite(self._output_zip, self.name, self._zip_name)
 
+
 def GetCareMap(which, imgname):
   """Returns the care_map string for the given partition.