move v2 api and capi to legacy

paddle/CMakeLists.txt

@@ -7,18 +7,18 @@ if(NOT WITH_FLUID_ONLY)
   add_subdirectory(legacy/parameter)
 
   if(MOBILE_INFERENCE)
-    add_subdirectory(capi)
+    add_subdirectory(legacy/capi)
   else()
     add_subdirectory(legacy/pserver)
     add_subdirectory(trainer)
     add_subdirectory(scripts)
 
     if(WITH_C_API)
-      add_subdirectory(capi)
+      add_subdirectory(legacy/capi)
     endif()
 
     if(WITH_SWIG_PY)
-      add_subdirectory(api)
+      add_subdirectory(legacy/api)
     endif()
   endif()
 endif()