correct the secretKey filename in getAuthenticationService function #603

Job	Run time
testsuite / testsuite-linux (8.1, highest, false)	30s
testsuite / testsuite-linux (8.2, highest, false)	32s
cs-stan / Coding Standard & Static Analysis	28s
testsuite / testsuite-linux (8.4, highest, false)	1m 14s
testsuite / testsuite-linux (8.3, highest, false)	40s
testsuite / testsuite-linux (8.1, lowest, false)	27s
	3m 51s

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