gn2bp: change remove to discard

This is probably not useful anymore, will work on removing some of this
soon.

Test: //components/cronet/android:cronet
Change-Id: I4740537972c9bf522abeb93a0306d981c8e71162
diff --git a/tools/gn2bp/gen_android_bp b/tools/gn2bp/gen_android_bp
index 420f851..4e33a7a 100755
--- a/tools/gn2bp/gen_android_bp
+++ b/tools/gn2bp/gen_android_bp
@@ -1163,7 +1163,7 @@
     module.srcs.clear()
   elif module.name == "cronet_aml_third_party_boringssl_boringssl":
     x86_srcs = module.srcs.copy()
-    x86_srcs.remove(":cronet_aml_third_party_boringssl_boringssl_asm")
+    x86_srcs.discard(":cronet_aml_third_party_boringssl_boringssl_asm")
     x86_srcs.add(":cronet_aml_third_party_boringssl_boringssl_asm_x86")
     module.arch['x86'] = {'srcs': x86_srcs}
     module.arch['x86_64'] = {'srcs': module.srcs.copy()}