set libbson submodule to 1.2.0

ajdavis · ajdavis · commit 44958304f799 · 2015-10-13T14:50:42.000-04:00
diff --git a/src/libbson b/src/libbson
@@ -1 +1 @@
-Subproject commit 68907621daf0466c49cacde3a42dc0b38c96e0f9
+Subproject commit e434c354a3939db063ee78345834baed19002f7e
