test/librbd/fsx.c: fix indentation (NESTING_INDENT_MISMATCH)

Fix indentation to the same as the original fsx.c .

Fix for Coverity issue:

CID 1219473 (#1-2 of 2): Nesting level does not match indentation
(NESTING_INDENT_MISMATCH)
 uncle: This statement is indented to column 25, as if it were
 nested within the preceding parent statement, but it is not.

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>