Fix Windows native symbol uploads.

- We were appending a CRLF to uploaded files, which is okay for Breakpad
  symbols but breaks binaries (PE/PDB).
- Removed the CRLF after files in the request body to fix issue. Tested with
  Breakpad, PE, and PDB uploads.

Change-Id: I95ee7c51bf981cdb2e55cc720a7813cf7afa21ce
Reviewed-on: https://chromium-review.googlesource.com/c/breakpad/breakpad/+/4038506
Reviewed-by: Joshua Peraza <jperaza@chromium.org>
Reviewed-by: Zequan Wu <zequanwu@google.com>

src/common/windows/http_upload.cc

@@ -390,7 +390,6 @@ namespace {
     if (!contents.empty()) {
       request_body->append(&(contents[0]), contents.size());
     }
-    request_body->append("\r\n");
 
     return true;
   }