Re: t1308-config-set.sh fails on current master

> t1308-config-set.sh fails on current master (v2.13.1-449-g02a2850ad58e). 
> The error is introduced by commit e2d90fd1c33a ("config.mak.uname: set 
> FREAD_READS_DIRECTORIES for Linux and FreeBSD"). Reverting the commit 
> results in a conflict, but the test works on the commit before, 
> 02912f477586.
>
> Tested on
>
>   Debian GNU/Linux 8.8 (jessie)
>   Linux Mint 18 Sarah

> Test output:
> 
>   $ ./t1308-config-set.sh
>   ok 1 - setup default config
>   ok 2 - get value for a simple key
>   ok 3 - get value for a key with value as an empty string
>   ok 4 - get value for a key with value as NULL
>   ok 5 - upper case key
>   ok 6 - mixed case key
>   ok 7 - key and value with mixed case
>   ok 8 - key with case sensitive subsection
>   ok 9 - key with case insensitive section header
>   ok 10 - key with case insensitive section header & variable
>   ok 11 - find value with misspelled key
>   ok 12 - find value with the highest priority
>   ok 13 - find integer value for a key
>   ok 14 - find string value for a key
>   ok 15 - check line error when NULL string is queried
>   ok 16 - find integer if value is non parse-able
>   ok 17 - find bool value for the entered key
>   ok 18 - find multiple values
>   ok 19 - find value from a configset
>   ok 20 - find value with highest priority from a configset
>   ok 21 - find value_list for a key from a configset
>   ok 22 - proper error on non-existent files
>   not ok 23 - proper error on directory "files"
>   #
>   #               echo "Error (-1) reading configuration file a-directory." >expect &&
>   #               mkdir a-directory &&
>   #               test_expect_code 2 test-config configset_get_value foo.bar a-directory 2>output &&
>   #               grep "^warning:" output &&
>   #               grep "^Error" output >actual &&
>   #               test_cmp expect actual
>   #
>   ok 24 - proper error on non-accessible files
>   ok 25 - proper error on error in default config files
>   ok 26 - proper error on error in custom config files
>   ok 27 - check line errors for malformed values
>   ok 28 - error on modifying repo config without repo
>   ok 29 - iteration shows correct origins
>   # failed 1 among 29 test(s)
>   1..29