Fixed the following warning generated when using cmake3:

CMake Warning (dev) at
/usr/share/cmake3/Modules/FindPackageHandleStandardArgs.cmake:272
(message):
  The package name passed to `find_package_handle_standard_args` (gRPC)
does
  not match the name of the calling package (GRPC).  This can lead to
  problems in calling code that expects `find_package` result variables
  (e.g., `_FOUND`) to follow a certain pattern.
Call Stack (most recent call first):
  cmake/FindGRPC.cmake:125 (FIND_PACKAGE_HANDLE_STANDARD_ARGS)
  eos_cta/CMakeLists.txt:19 (find_package)
This warning is for project developers.  Use -Wno-dev to suppress it.