travis: remove hardcoded DWITH_SSL option (#278)
travis: remove hardcoded DWITH_SSL option (#278)

It causes CMAKE configuration error because of failing to detect
installed OpenSSL library on that system

  --
  Wrong option or path for
  WITH_SSL=/export/home/pb2/build/sb_0-36131509-1569568392.28/dep2.

  Make sure you have specified a supported SSL version.

  Valid options are :

  system (use the OS openssl library),

  yes (synonym for system),

  </path/to/custom/openssl/installation>

  CMake Error at cmake/ssl.cmake:66 (MESSAGE):

    Please install the appropriate openssl developer package.

  Call Stack (most recent call first):

    cmake/ssl.cmake:265 (FATAL_SSL_NOT_FOUND_ERROR)

    CMakeLists.txt:573 (MYSQL_CHECK_SSL)

  -- Configuring incomplete, errors occurred!
mroonga/mroonga,mroonga/mroonga,mroonga/mroonga,mroonga/mroonga