Integration build a small memory image

Modify one of the integration builds so that that the
OPENSSL_SMALL_MEMORY option is compiled. There doesn't appear to be an
automatic build with this option set.

I think the options in the modified build are covered elsewhere (without
the small memory) but a new job might still be preferable.
Reviewed-by: NRich Salz <rsalz@openssl.org>
Reviewed-by: NMatt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3268)

.travis.yml

@@ -121,7 +121,7 @@ matrix:
                   sources:
                       - ubuntu-toolchain-r-test
           compiler: gcc-5
-          env: EXTENDED_TEST="yes" CONFIG_OPTS="no-asm enable-ubsan enable-rc5 enable-md2 enable-aria -DPEDANTIC" OPENSSL_TEST_RAND_ORDER=0
+          env: EXTENDED_TEST="yes" CONFIG_OPTS="no-asm enable-ubsan enable-rc5 enable-md2 enable-aria -DPEDANTIC -DOPENSSL_SMALL_FOOTPRINT" OPENSSL_TEST_RAND_ORDER=0
         - os: linux
           addons:
               apt: