Revert "tools: s/strncpy()/strlcpy()/g"

Revert "tools: s/strncpy()/strlcpy()/g"

This reverts commit 2ec47d5149e73db97f7877d06d67cb11421097bb.

First, I forgot to actually replace strncpy() with strlcpy(). Second, we don't
want to \0-terminate since this is an abstract unix socket and this is not
required. Instead, let's simply use memcpy() which is more correct and also
silences gcc-8.

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>