[OnionSoup] Repair typemapping for EncodedFormData, FormDataElement, etc.

The previous CL about typemaping for EncodedFormData, FormDataElement,
and HTTPHeaderMap didn't enable, for "type_mappings" definition in
related .typemap files has addtional blank before and after "=".
This CL repair this bug.

Bug: 860403
Change-Id: I84e32e95a25851c2abc2606a86ed34feb5b3b1d1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1581164
Reviewed-by: Leon Han <leon.han@intel.com>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Commit-Queue: Richard Li <richard.li@intel.com>
Cr-Commit-Position: refs/heads/master@{#654277}
6 files changed