Use UintToString rather than IntToString in version.cc

base/version.cc

Index: base/version.cc
diff --git a/base/version.cc b/base/version.cc
index 228dcb8aef20e4a33d9dd03269ceaa5195ba1a32..3677b731980beb8328a1b6b0633c791cd1dee44e 100644
--- a/base/version.cc
+++ b/base/version.cc
@@ -168,10 +168,10 @@ const std::string Version::GetString() const {
   std::string version_str;
   size_t count = components_.size();
   for (size_t i = 0; i < count - 1; ++i) {
-    version_str.append(IntToString(components_[i]));
+    version_str.append(UintToString(components_[i]));
     version_str.append(".");
   }
-  version_str.append(IntToString(components_[count - 1]));
+  version_str.append(UintToString(components_[count - 1]));
   return version_str;
 }