Fix SSL_get0_chain_certs.

SSL_get0_chain_certs calls a ctrl function with
SSL_CTRL_GET_CHAIN_CERTS. The switch failed to set a positive return
value and so the call always appeared to fail.

(Imported from upstream's
https://boringssl-review.googlesource.com/#/c/4521/)

Change-Id: Ia69c404c528b0cb01c7ff5e56ca8a8415265fa73
1 file changed