Remove iscsi_queue_pdu from the list of symbols otherwise clang on OSX
fails to compile with the following error:
Undefined symbols for architecture x86_64:
"_iscsi_queue_pdu", referenced from:
-exported_symbol[s_list] command line option
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)