Place RTI OpenSSL on the (LD_LIBRARY_)PATH on Linux (#263)
Place RTI OpenSSL on the (LD_LIBRARY_)PATH on Linux (#263)

* use RTI_OPENSSL env vars for tests

* pass PATH to tests directly

* remove dead code and add comments

* read env once and modify env var in a platform agnostic way

* use TO_CMAKE_PATH

* modify path only for Linux for now

just pass unchanged PATH on other platforms

Modify PATH only if connext is being tested

modify path for all connext tests (not sure why it worked before)

* TEST_PATH_WITH_RTI_BIN -> TEST_PATH

ros2/system_tests,ros2/system_tests