openssl-cmp.pod.in: fix grammar glitch #1125

Job	Run time
run-checker (no-cmp)	7m 10s
run-checker (no-cms)	8m 35s
run-checker (no-dgram)	7m 0s
run-checker (no-dh)	7m 49s
run-checker (no-dtls)	10m 8s
run-checker (no-ec)	6m 14s
run-checker (no-ec2m)	8m 10s
run-checker (no-ecx)	7m 4s
run-checker (no-http)	7m 11s
run-checker (no-legacy)	8m 52s
run-checker (no-sock)	6m 36s
run-checker (enable-ssl-trace)	7m 37s
run-checker (no-threads)	7m 39s
run-checker (no-thread-pool)	7m 29s
run-checker (no-default-thread-pool)	9m 46s
run-checker (no-tls)	7m 1s
run-checker (no-tls1_2)	6m 54s
run-checker (no-tls1_3)	8m 18s
run-checker (enable-trace enable-fips)	7m 56s
run-checker (no-ui)	9m 4s
run-checker (no-quic)	7m 24s
	2h 43m 57s

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