Fix Qt5 version requirement (#213)

- Use rviz_QT_VERSION
- Drop OpenGL dependency

Author: rhaschke

rviz_imu_plugin/CMakeLists.txt

@@ -14,9 +14,7 @@ if(rviz_QT_VERSION VERSION_LESS "5")
   include(${QT_USE_FILE})
 else()
   message(STATUS "Using Qt5 based on the rviz_QT_VERSION: ${rviz_QT_VERSION}")
-  find_package(Qt5Widgets REQUIRED)
-  find_package(Qt5Core REQUIRED)
-  find_package(Qt5OpenGL REQUIRED)
+  find_package(Qt5 ${rviz_QT_VERSION} REQUIRED Core Widgets)
   ## Set the QT_LIBRARIES variable for Qt5, so it can be used below.
   set(QT_LIBRARIES Qt5::Widgets)
 endif()