fix CMake CMP0054 warning:

ported from c105b72945

cmake/OpenCVModule.cmake

@@ -787,7 +787,7 @@ macro(__ocv_parse_test_sources tests_type)
       set(__file_group_sources "")
     elseif(arg STREQUAL "DEPENDS_ON")
       set(__currentvar "OPENCV_${tests_type}_${the_module}_DEPS")
-    elseif("${__currentvar}" STREQUAL "__file_group_sources" AND NOT __file_group_name)
+    elseif(" ${__currentvar}" STREQUAL " __file_group_sources" AND NOT __file_group_name) # spaces to avoid CMP0054
       set(__file_group_name "${arg}")
     else()
       list(APPEND ${__currentvar} "${arg}")

cmake/OpenCVUtils.cmake

@@ -276,12 +276,12 @@ macro(OCV_OPTION variable description value)
     endif()
   endforeach()
   unset(__varname)
-  if("${__condition}" STREQUAL "")
+  if(__condition STREQUAL "")
     set(__condition 2 GREATER 1)
   endif()
 
   if(${__condition})
-    if("${__value}" MATCHES ";")
+    if(__value MATCHES ";")
       if(${__value})
         option(${variable} "${description}" ON)
       else()