Removing #defines previously used for building without BoringSSL/OpenSSL.

These defines don't work any more, so they only cause confusion:

FEATURE_ENABLE_SSL
HAVE_OPENSSL_SSL_H
SSL_USE_OPENSSL

BUG=webrtc:7025

Review-Url: https://codereview.webrtc.org/2640513002
Cr-Commit-Position: refs/heads/master@{#16196}

webrtc/api/peerconnectioninterface_unittest.cc

@@ -293,12 +293,6 @@ static const char kSdpStringMs1Video1[] =
     "a=ssrc:4 cname:stream1\r\n"
     "a=ssrc:4 msid:stream1 videotrack1\r\n";
 
-#define MAYBE_SKIP_TEST(feature)                    \
-  if (!(feature())) {                               \
-    LOG(LS_INFO) << "Feature disabled... skipping"; \
-    return;                                         \
-  }
-
 using ::testing::Exactly;
 using cricket::StreamParams;
 using webrtc::AudioSourceInterface;
@@ -2042,7 +2036,6 @@ TEST_F(PeerConnectionInterfaceTest, TestRejectDataChannelInAnswer) {
 // FireFox, use it as a remote session description, generate an answer and use
 // the answer as a local description.
 TEST_F(PeerConnectionInterfaceTest, ReceiveFireFoxOffer) {
-  MAYBE_SKIP_TEST(rtc::SSLStreamAdapter::HaveDtlsSrtp);
   FakeConstraints constraints;
   constraints.AddMandatory(webrtc::MediaConstraintsInterface::kEnableDtlsSrtp,
                            true);