BUILD: travis-ci: get back to osx without openssl support

there's some issue with socket path, after it is resolved,
we will enable openssl for osx
diff --git a/.travis.yml b/.travis.yml
index 4dd7e9a..159e0d0 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -44,7 +44,7 @@
     env: TARGET=linux2628 FLAGS=
   - os: osx
     compiler: clang
-    env: TARGET=generic FLAGS="USE_OPENSSL=1" OPENSSL_VERSION=1.1.1b
+    env: TARGET=generic FLAGS=
 
 install:
   - git clone https://github.com/VTest/VTest.git ../vtest