BUILD: CI: temporarily mark openssl-1.0.2 as allowed failure

Until #429 is resolved, let us ignore openssl-1.0.2 failures
diff --git a/.travis.yml b/.travis.yml
index 9046e6d..a0d9502 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -99,6 +99,12 @@
     before_script:
       - git clone http://git.1wt.eu/git/libslz.git/
       - cd libslz && make && make PREFIX=${HOME}/opt install && cd ..
+  allow_failures:
+  - os: linux
+    arch: ppc64le
+    if: type == cron
+    compiler: gcc
+    env: TARGET=linux-glibc OPENSSL_VERSION=1.0.2u
 
 install:
   - git clone https://github.com/VTest/VTest.git ../vtest