remove deprecated "nokmem" build-tag for runc

This build-tag was removed in https://github.com/opencontainers/runc/commit/52390d68040637dfc77f9fda6bbe70952423d380,
which is part of runc v1.0.0-rc94 and up, so no longer relevant.

the kmem options are now always disabled in runc.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

hack/dockerfile/install/runc.installer

@@ -1,4 +1,5 @@
 #!/bin/sh
+set -e
 
 # When updating RUNC_COMMIT, also update runc in vendor.conf accordingly
 # The version of runc should match the version that is used by the containerd
@@ -7,13 +8,7 @@
 : ${RUNC_COMMIT:=52b36a2dd837e8462de8e01458bf02cf9eea47dd} # v1.0.2
 
 install_runc() {
-	# If using RHEL7 kernels (3.10.0 el7), disable kmem accounting/limiting
-	if uname -r | grep -q '^3\.10\.0.*\.el7\.'; then
-		: ${RUNC_NOKMEM='nokmem'}
-	fi
-
-	# Do not build with ambient capabilities support
-	RUNC_BUILDTAGS="${RUNC_BUILDTAGS:-"seccomp $RUNC_NOKMEM"}"
+	RUNC_BUILDTAGS="${RUNC_BUILDTAGS:-"seccomp"}"
 
 	echo "Install runc version $RUNC_COMMIT (build tags: $RUNC_BUILDTAGS)"
 	git clone https://github.com/opencontainers/runc.git "$GOPATH/src/github.com/opencontainers/runc"