Make GetInstalledVersion more verbose on failures

This issue is related to the GetInstalledVersionLinuxTest.WithVersion
test where, unlike on Windows or MacOS, querying Chrome's version
relies on the content of the console output of a child process. This
cl makes GetInstalledVersion() slightly more verbose in order to make
it easy to identify potential warnings (or any other console outputs)
when querying the version.

Bug: chromium:1152832
Change-Id: Iea153887d3f1e439c1a6305b88c93dfef17cc4f1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2560609
Commit-Queue: Greg Thompson <grt@chromium.org>
Reviewed-by: Greg Thompson <grt@chromium.org>
Cr-Commit-Position: refs/heads/master@{#835113}

chrome/browser/upgrade_detector/get_installed_version_linux.cc

@@ -27,7 +27,8 @@ InstalledAndCriticalVersion GetInstalledVersion() {
   // Failure may be a result of invoking a Chrome that predates the introduction
   // of the --product-version switch in https://crrev.com/48795 (6.0.424.0).
   DLOG_IF(ERROR, !installed_version.IsValid())
-      << "Failed to get current file version";
+      << "Failed to get current file version; child process replied with: "
+      << reply;
 
   return InstalledAndCriticalVersion(std::move(installed_version));
 }