Fix Travis failure with test install

Signed-off-by: Alain <alainmarcel@yahoo.com>

.travis.yml

diff --git a/.travis.yml b/.travis.yml
index cbc3e82..865cd7d 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -36,5 +36,5 @@
 script:
   - make release
   - sudo make install
+  - make test_install
 
-  

Makefile

diff --git a/Makefile b/Makefile
index 4831233..4a46e34 100644
--- a/Makefile
+++ b/Makefile
@@ -24,6 +24,8 @@
 
 install:
 	cd build; make install
+
+test_install:
 	cd tests/TestInstall; rm -rf build; mkdir -p build; cd build; cmake ../ -DINSTALL_DIR=/usr/local; make ; ./test_hellosureworld --version
 
 uninstall: