ustream-ssl: fix build against wolfSSL

commit 39a6ce205d (ustream-ssl: Enable ECDHE with OpenSSL.) broke
build against wolfSSL because wolfSSL doesn't (yet) support
SSL_CTX_set_ecdh_auto() of the OpenSSL API.

Fix this in ustream-ssl:

 189cd38b41 don't use SSL_CTX_set_ecdh_auto with wolfSSL

Signed-off-by: Daniel Golle <daniel@makrotopia.org>

package/libs/ustream-ssl/Makefile

@@ -5,9 +5,9 @@ PKG_RELEASE:=1
 
 PKG_SOURCE_PROTO:=git
 PKG_SOURCE_URL=$(PROJECT_GIT)/project/ustream-ssl.git
-PKG_SOURCE_DATE:=2018-05-22
-PKG_SOURCE_VERSION:=5322f9db23b69fdc2b4760a6cfd67848a11818a4
-PKG_MIRROR_HASH:=c943f6e603b1309b33fd276acddffb33a171b6370455b6c21200897012e42d05
+PKG_SOURCE_DATE:=2018-05-24
+PKG_SOURCE_VERSION:=189cd38b4188bfcb4c8cf67d8ae71741ffc2b906
+PKG_MIRROR_HASH:=114d229828d95229e2b7134f668c0d2c3cee63ffa90e970d4c50a331f505b17d
 CMAKE_INSTALL:=1
 
 PKG_BUILD_DIR=$(BUILD_DIR)/$(PKG_NAME)-$(BUILD_VARIANT)/$(PKG_SOURCE_SUBDIR)