Exported Excel with negative number can't be opened by MS Office

[hauso]

Preconditions

XML excel generator class contain error causing file can't be opened by MS Office.
In Open Office is file opened without problem

1. Magento 2.x version + MS Office XML handler

Steps to reproduce

1. Generate some XML export with negative value (eg. quantity)
2. Try to open it with Office XML handler

Expected result

1. Open export file

Actual result

1. File do not open correctly and Office's error log is created containing information about incorrect value eg.:

XML ERROR in Table
REASON: Bad Value
FILE: C:\Tomas\products_20171025134557.xml
GROUP: Cell
TAG: Data
VALUE: -1

I tested Microsoft Office Professional Plus 2013 and OpenOffice Calc 4.1.3 only.
Open Office can open file without problem, MS Office do not open file and create error report.

[magento-team]

Internal ticket to track issue progress: MAGETWO-82851