Merge branch 'mem-0.3.1' into 'branch-0.3.1'

MS-190: use env variable to switch mem manager and fix cmake

See merge request megasearch/milvus!180

Former-commit-id: a839cb38ff916da6b197c40185457e7537549a17

cpp/cmake/ThirdPartyPackages.cmake

@@ -534,7 +534,7 @@ if(MILVUS_BOOST_VENDORED)
             ""
             ${EP_LOG_OPTIONS})
     set(Boost_INCLUDE_DIR "${BOOST_PREFIX}")
-    set(Boost_INCLUDE_DIRS "${BOOST_INCLUDE_DIR}")
+    set(Boost_INCLUDE_DIRS "${Boost_INCLUDE_DIR}")
     add_dependencies(boost_system_static boost_ep)
     add_dependencies(boost_filesystem_static boost_ep)
     add_dependencies(boost_serialization_static boost_ep)

cpp/unittest/db/CMakeLists.txt

@@ -24,6 +24,8 @@ link_directories("/usr/local/cuda/lib64")
 
 include_directories(/usr/include/mysql)
 
+#add_definitions(-DBOOST_ERROR_CODE_HEADER_ONLY)
+
 set(db_test_src
     #${unittest_srcs}
     ${config_files}
@@ -59,6 +61,6 @@ set(knowhere_libs
         cublas
         )
 
-target_link_libraries(db_test ${db_libs} ${unittest_libs} ${knowhere_libs})
+target_link_libraries(db_test ${knowhere_libs} ${db_libs} ${unittest_libs})
 
 install(TARGETS db_test DESTINATION bin)