cmake: s/NPM/NPM_EXECUTABLE/

so the naming is more consistent with other executables found by
find_program().

Signed-off-by: Kefu Chai <kchai@redhat.com>

CMakeLists.txt

@@ -630,8 +630,8 @@ include_directories(BEFORE SYSTEM ${Boost_INCLUDE_DIRS})
 option(WITH_MGR_DASHBOARD_FRONTEND "Build the mgr/dashboard frontend using `npm`" ON)
 option(WITH_SYSTEM_NPM "Assume that dashboard build tools already installed through packages" OFF)
 if(WITH_SYSTEM_NPM)
-  find_program(NPM npm)
-  if(NOT NPM)
+  find_program(NPM_EXECUTABLE npm)
+  if(NOT NPM_EXECUTABLE)
     message(FATAL_ERROR "Can't find npm.")
   endif()
 endif()

src/pybind/mgr/dashboard/frontend/CMakeLists.txt

@@ -13,7 +13,7 @@ function(add_npm_command)
   else()
     string(REGEX REPLACE
       "^([^ ]=[^ ] )*npm (.*)$"
-      "\\1${NPM} \\2"
+      "\\1${NPM_EXECUTABLE} \\2"
       command ${command})
   endif()
   string(REPLACE " " ";" command "${command}")