test eventlog: fix check eventlog.sh if efivar.h exists #1621

Job	Run time
coverity-test	0s
master-tss-build-test (gcc)	17m 53s
build-test (ubuntu-18.04, gcc)	5m 47s
coverage-test	5m 56s
build-test (ubuntu-18.04, clang)	5m 3s
master-tss-build-test (clang)	5m 1s
build-test (ubuntu-20.04, gcc)	5m 54s
build-test (ubuntu-20.04, clang)	5m 2s
build-test (fedora-30, gcc)	5m 52s
build-test (fedora-30, clang)	5m 17s
build-test (opensuse-leap, gcc)	6m 1s
build-test (opensuse-leap, clang)	5m 11s
build-test (fedora-32, gcc)	5m 51s
build-test (fedora-32, clang)	5m 7s
build-test (ubuntu-22.04, gcc)	11m 13s
build-test (ubuntu-22.04, clang)	10m 45s
	1h 45m 53s

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