xfs/205: Fix that b2 variable is treated as octal vaule

xfs/205: Fix that b2 variable is treated as octal vaule

Running xfs/205 triggers the following error:
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QA output created by 205
+./tests/xfs/205: line 61: 098: value too great for base (error token is "098")
...
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If b2 variable is a 2-digit number beginning with 0(e.g. 098),
it will be treated as octal vaule instaed of decimal value.  We
try to declare it as decimal value forcely.

Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
Reviewed-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>