Remove improper build_with_mozilla clauses in rtc_base BUILD.gn

rtc_build_ssl is defined to be !build_with_mozilla, but we have
tautological if conditions involving both. This removes the offending
clauses for now. It makes more sense to address the problem during the
next import of webrtc.org code into Firefox.

Bug: webrtc:8670
Change-Id: I586deb7c33566efae6bb6380c9d4ae61a0fe1c37
Reviewed-on: https://webrtc-review.googlesource.com/39960
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Patrik Höglund <phoglund@webrtc.org>
Commit-Queue: Dan Minor <dminor@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#21662}
diff --git a/rtc_base/BUILD.gn b/rtc_base/BUILD.gn
index 74bb964..0b8e9ae 100644
--- a/rtc_base/BUILD.gn
+++ b/rtc_base/BUILD.gn
@@ -55,7 +55,7 @@
   }
 }
 
-if (!rtc_build_ssl && !build_with_mozilla) {
+if (!rtc_build_ssl) {
   config("external_ssl_library") {
     assert(rtc_ssl_root != "",
            "You must specify rtc_ssl_root when rtc_build_ssl==0.")
@@ -703,7 +703,7 @@
 
   if (rtc_build_ssl) {
     deps += [ "//third_party/boringssl" ]
-  } else if (!build_with_mozilla) {
+  } else {
     configs += [ ":external_ssl_library" ]
   }