MDEV-26912 Spider: Remove dead code related to Oracle OCI

Remove the dead-code, in Spider, which is related to the Spider's
Oracle OCI support. The code has been disabled for a long time and
it is unlikely that the code will be enabled.

Author: nayuta-yanagisawa

storage/spider/CMakeLists.txt

@@ -17,17 +17,9 @@ SET(SPIDER_SOURCES
   spd_param.cc spd_sys_table.cc spd_trx.cc spd_db_conn.cc spd_conn.cc
   spd_table.cc spd_direct_sql.cc spd_udf.cc spd_ping_table.cc
   spd_copy_tables.cc spd_i_s.cc spd_malloc.cc ha_spider.cc spd_udf.def
-  spd_db_mysql.cc spd_db_oracle.cc spd_group_by_handler.cc spd_db_include.cc
+  spd_db_mysql.cc spd_group_by_handler.cc spd_db_include.cc
 )
 
-IF(DEFINED ENV{ORACLE_HOME})
-  SET(ORACLE_HOME $ENV{ORACLE_HOME})
-  FIND_PATH(ORACLE_INCLUDE_DIR oci.h PATHS ${ORACLE_HOME}/rdbms/public)
-  SET(ORACLE_OCI_LIB_NAME clntsh)
-  SET(ORACLE_LIB_DIR ${ORACLE_HOME}/lib)
-  FIND_LIBRARY(ORACLE_OCI_LIBRARY NAMES ${ORACLE_OCI_LIB_NAME} PATHS ${ORACLE_LIB_DIR})
-ENDIF()
-
 IF(EXISTS ${PROJECT_SOURCE_DIR}/storage/mysql_storage_engine.cmake)
   SET(CMAKE_CXX_FLAGS_DEBUG
     "${CMAKE_CXX_FLAGS_DEBUG} -DSAFEMALLOC -DSAFE_MUTEX -DUSE_SYMDIR /Zi")
@@ -60,16 +52,6 @@ ELSE()
   ENDIF()
 ENDIF()
 
-IF(ORACLE_INCLUDE_DIR AND ORACLE_OCI_LIBRARY)
-  SET(SPIDER_WITH_ORACLE_OCI OFF CACHE BOOL "Spider is compiled with Oracle OCI library.")
-  IF(SPIDER_WITH_ORACLE_OCI)
-    SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -DHAVE_ORACLE_OCI -DLINUX -D_GNU_SOURCE -D_REENTRANT")
-    SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -DHAVE_ORACLE_OCI -DLINUX -D_GNU_SOURCE -D_REENTRANT")
-    INCLUDE_DIRECTORIES(${ORACLE_INCLUDE_DIR})
-    TARGET_LINK_LIBRARIES (spider ${ORACLE_OCI_LIBRARY})
-  ENDIF()
-ENDIF()
-
 IF(MSVC AND (TARGET spider))
   IF (CMAKE_BUILD_TYPE STREQUAL "Debug")
     ADD_CUSTOM_COMMAND(TARGET spider