disable autovec on 32 *and* 64 bit builds for horiz. convolve

disable autovec on 32 *and* 64 bit builds for horiz. convolve

Works around some garbage bottom rows for certain scaled images.  Will land a separate GM that demonstrates.

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/4e4b935d526f5720b3f15c4742eef84d49ebb984

[humper, 2014-08-28 20:47:56]

humper@google.com changed reviewers:
+ mtklein@google.com

[humper, 2014-08-28 20:48:04]

ptal

[humper, 2014-08-28 20:48:41]

The CQ bit was checked by humper@google.com

[commit-bot: I haz the power, 2014-08-28 20:48:50]

CQ is trying da patch. Follow status at
 https://skia-tree-status.appspot.com/cq/humper@google.com/513833003/1

[commit-bot: I haz the power, 2014-08-28 20:48:51]

Note for Reviewers:
The CQ is waiting for an approval.
If you believe that the CL is not ready yet, or if you would like to L-G-T-M
with comments then please uncheck the CQ checkbox.

Waiting for LGTM from a valid reviewer till 2014-08-29 02:48 UTC

[mtklein, 2014-08-28 20:50:14]

lgtm

[commit-bot: I haz the power, 2014-08-28 21:01:36]

Committed patchset #1 (id:1) as 4e4b935d526f5720b3f15c4742eef84d49ebb984