Update protobuf sources (no core revision change)

Ilya Bogdanov · Ilya Bogdanov · commit a0a7acca894e · 2020-01-09T12:20:57.000+03:00
diff --git a/exonum-java-binding/common/src/main/proto b/exonum-java-binding/common/src/main/proto
@@ -1 +1 @@
-Subproject commit c2155247de7e3677794d3626a95dbaf2d470cd0b
+Subproject commit 4fa9cad32440c0cbbdab9d1c92f7366c6be88c2f
