Verify checksum after downloading sysdig tarball

Also it seemed that any of value of -DSYSDIG_VERSION
failed to propagate, from first cmake to second cmake.

Signed-off-by: Anders F Björklund <anders.f.bjorklund@gmail.com>

cmake/modules/sysdig-repo/CMakeLists.txt

@@ -22,12 +22,13 @@ include(ExternalProject)
 # In case you want to test against another sysdig version just pass the variable - ie., `cmake -DSYSDIG_VERSION=dev ..`
 if(NOT SYSDIG_VERSION)
   set(SYSDIG_VERSION "146a431edf95829ac11bfd9c85ba3ef08789bffe")
+  set(SYSDIG_CHECKSUM "SHA256=6e477ac5fe9d3110b870bd4495f01541373a008c375a1934a2d1c46798b6bad6")
 endif()
 
 ExternalProject_Add(
   sysdig
   URL "https://github.com/draios/sysdig/archive/${SYSDIG_VERSION}.tar.gz"
-  # URL_HASH SHA256=bd09607aa8beb863db07e695863f7dc543e2d39e7153005759d26a340ff66fa5
+  URL_HASH "${SYSDIG_CHECKSUM}"
   CONFIGURE_COMMAND ""
   BUILD_COMMAND ""
   INSTALL_COMMAND ""

cmake/modules/sysdig.cmake

@@ -22,7 +22,7 @@ endif()
 
 file(MAKE_DIRECTORY ${SYSDIG_CMAKE_WORKING_DIR})
 # cd /path/to/build && cmake /path/to/source
-execute_process(COMMAND "${CMAKE_COMMAND}" ${SYSDIG_CMAKE_SOURCE_DIR} WORKING_DIRECTORY ${SYSDIG_CMAKE_WORKING_DIR})
+execute_process(COMMAND "${CMAKE_COMMAND}" -DSYSDIG_VERSION=${SYSDIG_VERSION} ${SYSDIG_CMAKE_SOURCE_DIR} WORKING_DIRECTORY ${SYSDIG_CMAKE_WORKING_DIR})
 
 # todo(leodido, fntlnz) > use the following one when CMake version will be >= 3.13