m4: Fix check for Python 3.6 version. #2568

Job	Run time
linux rpm fedora	4m 30s
libreswan (ubuntu-24.04)	6s
linux deb no dpdk	4m 53s
dpdk gcc (ubuntu-24.04)	6s
osx clang --disable-ssl	1m 46s
clang-analyze-cache	11m 4s
linux gcc --disable-ssl	2m 47s
linux clang --disable-ssl	2m 29s
linux gcc c99	2m 42s
linux clang c99	2m 38s
linux gcc test	8m 53s
linux clang address,undefined test	16m 13s
linux gcc test --enable-shared	11m 36s
linux clang test --enable-shared	10m 52s
linux gcc check check-dpdk dpdk	18m 53s
linux clang check check-dpdk dpdk	18m 45s
linux gcc test -ljemalloc	10m 25s
linux clang test -ljemalloc	8m 50s
linux gcc --enable-afxdp	2m 48s
linux clang --enable-afxdp	2m 32s
linux gcc dpdk --enable-shared	3m 53s
linux clang dpdk --enable-shared	3m 43s
linux gcc dpdk-shared	2m 57s
linux clang dpdk-shared	3m 4s
linux gcc dpdk-shared --enable-shared	3m 52s
linux clang dpdk-shared --enable-shared	3m 46s
linux gcc m32 --disable-ssl	2m 50s
linux gcc check-ovsdb-cluster	6m 46s
linux gcc check-kernel -100	10m 58s
linux gcc check-kernel 100-	16m 18s
linux clang address,undefined check-kernel -100	13m 10s
linux clang address,undefined check-kernel 100-	18m 41s
linux gcc check-offloads -100	10m 0s
linux gcc check-offloads 100-	11m 54s
linux gcc dpdk check-system-userspace	12m 33s
linux clang address,undefined dpdk check-system-userspace	15m 58s
linux gcc dpdk check-system-tso	12m 11s
linux gcc dpdk check-afxdp	11m 50s
clang-analyze	10m 37s
	5h 17m 49s

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