suppresses ndk extract log

.travis.yml

@@ -35,7 +35,6 @@ addons:
     packages:
       - python2.7
       - libmagic1
-      - p7zip-full
 
 cache:
   directories:

scripts/install_android_ndk.sh

@@ -23,7 +23,7 @@ wget "http://dl.google.com/android/ndk/${ndk_installer_name}"
 
 chmod +x ${ndk_installer_name}
 
-./${ndk_installer_name} -y
+./${ndk_installer_name} -y 1>/dev/null
 
 rm ${ndk_installer_name}