Don't disable verity if VABC is disabled

Test: th
Change-Id: Icef5315047aa783219e1dcb6678adaa084626e52
diff --git a/tools/releasetools/ota_from_target_files.py b/tools/releasetools/ota_from_target_files.py
index 3d0fc67..02b2b4d 100755
--- a/tools/releasetools/ota_from_target_files.py
+++ b/tools/releasetools/ota_from_target_files.py
@@ -1052,8 +1052,10 @@
     target_info = common.BuildInfo(OPTIONS.target_info_dict, OPTIONS.oem_dicts)
     source_info = common.BuildInfo(OPTIONS.source_info_dict, OPTIONS.oem_dicts)
     vendor_prop = source_info.info_dict.get("vendor.build.prop")
-    if vendor_prop and \
-            vendor_prop.GetProp("ro.virtual_ab.compression.enabled") == "true":
+    vabc_used = vendor_prop and \
+        vendor_prop.GetProp("ro.virtual_ab.compression.enabled") == "true" and \
+        not OPTIONS.disable_vabc
+    if vabc_used:
       # TODO(zhangkelvin) Remove this once FEC on VABC is supported
       logger.info("Virtual AB Compression enabled, disabling FEC")
       OPTIONS.disable_fec_computation = True