Switch to cmake build on Travis CI so that it can, more easily, bypass lack of…

Switch to cmake build on Travis CI so that it can, more easily, bypass lack of OpenSSL in newer versions of OS X
Signed-off-by: Otavio Rodolfo Piske <opiske@redhat.com>

.travis.yml

@@ -7,6 +7,10 @@ compiler:
 os:
   - linux
   - osx
-  
+
+before_install:
+    - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; brew install openssl ; fi
+
 script:
-  - make
+  - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then mkdir build.paho ; cd build.paho; cmake -DPAHO_WITH_SSL=TRUE -DPAHO_BUILD_DOCUMENTATION=FALSE -DPAHO_BUILD_SAMPLES=TRUE .. ; fi
+  - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then make ; fi