TravisCI: wget cmake with --no-check-certificate

```
--2015-11-03 22:31:11--  http://www.cmake.org/files/v3.2/cmake-3.2.3-Linux-x86_64.sh
Resolving www.cmake.org (www.cmake.org)... 66.194.253.19
Connecting to www.cmake.org (www.cmake.org)|66.194.253.19|:80... connected.
HTTP request sent, awaiting response... 301 Moved Permanently
Location: http://cmake.org/files/v3.2/cmake-3.2.3-Linux-x86_64.sh [following]
--2015-11-03 22:31:11--  http://cmake.org/files/v3.2/cmake-3.2.3-Linux-x86_64.sh
Resolving cmake.org (cmake.org)... 66.194.253.19
Connecting to cmake.org (cmake.org)|66.194.253.19|:80... connected.
HTTP request sent, awaiting response... 301 Moved Permanently
Location: https://cmake.org/files/v3.2/cmake-3.2.3-Linux-x86_64.sh [following]
--2015-11-03 22:31:11--  https://cmake.org/files/v3.2/cmake-3.2.3-Linux-x86_64.sh
Connecting to cmake.org (cmake.org)|66.194.253.19|:443... connected.
ERROR: no certificate subject alternative name matches
        requested host name `cmake.org'.
To connect to cmake.org insecurely, use `--no-check-certificate'.
```