buildhistory: correctly handle reductions of numeric fields

(From OE-Core rev: 94fffb92e6a7a8021fb1acb06b9c4218703e23b2)

Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/lib/oe/buildhistory_analysis.py

@@ -308,7 +308,7 @@ def compare_dict_blobs(path, ablob, bblob, report_all):
                     percentchg = ((bval - aval) / float(aval)) * 100
                 else:
                     percentchg = 100
-                if percentchg < monitor_numeric_threshold:
+                if abs(percentchg) < monitor_numeric_threshold:
                     continue
             elif (not report_all) and key in list_fields:
                 if key == "FILELIST" and path.endswith("-dbg") and bstr.strip() != '':