Increase slack for inode estimation algorithm

This is required to prevent build failure on some targets.

Test: mmm
Bug: 119115481

Change-Id: Idf7c21b163a4e10e2ef435c2b2a7795a42feb200
diff --git a/tools/releasetools/build_image.py b/tools/releasetools/build_image.py
index 146b868..d710603 100755
--- a/tools/releasetools/build_image.py
+++ b/tools/releasetools/build_image.py
@@ -75,8 +75,8 @@
   """
   cmd = ["find", path, "-print"]
   output = common.RunAndCheckOutput(cmd, verbose=False)
-  # increase by 25 % as number of files and directories is not whole picture.
-  return output.count('\n') * 30 // 24
+  # TODO(b/122328872) Fix estimation algorithm to not need the multiplier.
+  return output.count('\n') * 2
 
 
 def GetFilesystemCharacteristics(sparse_image_path):