test: Use C locale instead of C.UTF-8

Gbp-Dch: ignore

test/integration/framework

@@ -442,7 +442,7 @@ EOF
 	# cleanup the environment a bit
 	# prefer our apt binaries over the system apt binaries
 	export PATH="${BUILDDIRECTORY}:${PATH}:/usr/local/sbin:/usr/sbin:/sbin"
-	export LC_ALL=C.UTF-8
+	export LC_ALL=C
 	unset LANGUAGE APT_CONFIG
 	unset GREP_OPTIONS DEB_BUILD_PROFILES
 	unset http_proxy HTTP_PROXY https_proxy HTTPS_PROXY no_proxy