fix MinidumpWriterTest.DeletedBinary for component build

Change-Id: Ifda6cb045e93cc7193bb31deb581ed9c8d4229d8
Reviewed-on: https://chromium-review.googlesource.com/628058
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#496968}

breakpad/BUILD.gn

@@ -772,6 +772,13 @@ if (is_linux || is_android) {
     ]
 
     configs += [ ":client_config" ]
+
+    if (is_component_build) {
+      ldflags = [
+        "-Wl,-rpath,",
+        rebase_path(root_build_dir),
+      ]
+    }
   }
 
   executable("generate_test_dump") {