t1300: create custom config file without special characters

t1300: create custom config file without special characters

Tests that required a custom configuration file to be created previously
used a file with non-alphanumeric characters including escaped double
quotes.  This is not really necessary for the majority of tests
involving custom config files, and decreases test coverage on systems
that dissallow such filenames (Windows, etc.).

Create two files, one appropriate for testing quoting and one
appropriate for general use.

Signed-off-by: Matthew Rogers <mattr94@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>