Add irt_random to szbuild link line.

Seems to be part of the non-sfi link now:
https://codereview.chromium.org/686723003/diff/180001/pnacl/driver/pnacl-translate.py

Otherwise I get:
x86-32-linux/lib/unsandboxed_irt.o:(.rodata+0x68): undefined reference to `nacl_secure_random'

BUG=none
R=stichnot@chromium.org

Review URL: https://codereview.chromium.org/726093002
1 file changed