rpc-layer: Fix undefined reference to g_strlcpy
fixes build with -Wl,-z,defs
/pkcs11/rpc-layer/gkm-rpc-module.c:238:(.text+0x1460): undefined reference to `g_strlcpy'
collect2: error: ld returned 1 exit status
make[3]: *** [Makefile:3572: gnome-keyring-pkcs11.la] Error 1