[vala/staging] Revert "vala: Drop mitigation in CodeContext.pkg_config_modversion() when it failed"

[Rico Tzschichholz <ricotz src gnome org>]

commit 2dc1851df13dcbe9969c48e35bc552d0ba0da418
Author: Rico Tzschichholz <ricotz ubuntu com>
Date:   Thu Apr 16 10:00:21 2020 +0200

    Revert "vala: Drop mitigation in CodeContext.pkg_config_modversion() when it failed"
    
    This reverts commit 09e565a511f43e48737b0bfb881ccfb32cf0ab82.

 vala/valacodecontext.vala | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
---
diff --git a/vala/valacodecontext.vala b/vala/valacodecontext.vala
index b79c06bdd..6ddcd8f5c 100644
--- a/vala/valacodecontext.vala
+++ b/vala/valacodecontext.vala
@@ -880,7 +880,10 @@ public class Vala.CodeContext {
                try {
                        Process.spawn_command_line_sync (pc, out output, null, out exit_status);
                        if (exit_status != 0) {
-                               output = null;
+                               output = output[0:-1];
+                               if (output == "") {
+                                       output = null;
+                               }
                        }
                } catch (SpawnError e) {
                        output = null;