test eventlog: fix check eventlog.sh if efivar.h exists #1619

Job	Run time
master-tss-build-test (gcc)	2m 42s
coverity-test	0s
coverage-test	2m 40s
master-tss-build-test (clang)	3m 1s
build-test (ubuntu-18.04, gcc)	2m 38s
build-test (ubuntu-18.04, clang)	2m 53s
build-test (ubuntu-20.04, gcc)	2m 41s
build-test (ubuntu-20.04, clang)	2m 50s
build-test (fedora-30, gcc)	2m 41s
build-test (fedora-30, clang)	2m 48s
build-test (opensuse-leap, gcc)	2m 47s
build-test (opensuse-leap, clang)	2m 35s
build-test (fedora-32, gcc)	2m 40s
build-test (fedora-32, clang)	2m 39s
build-test (ubuntu-22.04, gcc)	2m 31s
build-test (ubuntu-22.04, clang)	2m 52s
	40m 58s

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