Make right-sizing less aggressive

This is a rollback of Id5ae6645b9aa2d036e6fefe2fb17672e8f8ef6f0
and the followup I6a0f3919e8d45d0b3e7cd558a6ad4d3799012f2c

The magic constant introduced appears to be too aggressive.
Note that the new constant in I0f32c75e80b5da4d47671055ac274ccc2b485992
doesn't appear to fix the broken builds.

Bug: 111302946
Test: make
Change-Id: I29207265172d293c6fee98212e3266bde85895df
diff --git a/tools/releasetools/build_image.py b/tools/releasetools/build_image.py
index 0aeadaf..c3701a8 100755
--- a/tools/releasetools/build_image.py
+++ b/tools/releasetools/build_image.py
@@ -281,7 +281,7 @@
         logger.info(
             "Not worth reducing image %d <= %d.", free_size, reserved_size)
       else:
-        size -= free_size + (free_size // 61)
+        size -= free_size
         size += reserved_size
         if block_size <= 4096:
           size = common.RoundUpTo4K(size)