Put config in sync between gyp and gn.
Put config in sync between gyp and gn.

webrtc/base/base.gyp unconditionally set SSL_USE_OPENSSL and
HAVE_OPENSSL_SSL_H, fix webrtc/base/BUILD.gn to do the same.

Better implementation than https://codereview.webrtc.org/1441323002
to fix the same underlying issue (i.e. compilation on iOS).

BUG=459705

Review URL: https://codereview.webrtc.org/1812213002

Cr-Original-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#12078}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 0db3db94e5ddde90f37120c8b67866b5c7d5a5f0

Alkalyne/webrtctrunk,Alkalyne/webrtctrunk,jchavanton/webrtc,Alkalyne/webrtctrunk,jchavanton/webrtc,jchavanton/webrtc,Alkalyne/webrtctrunk,Alkalyne/webrtctrunk,jchavanton/webrtc,jchavanton/webrtc,Alkalyne/webrtctrunk,Alkalyne/webrtctrunk,Alkalyne/webrtctrunk,jchavanton/webrtc,jchavanton/webrtc