Improve help message of ssl_*2.c
diff --git a/programs/ssl/ssl_client2.c b/programs/ssl/ssl_client2.c
index 758ebf3..c090db9 100644
--- a/programs/ssl/ssl_client2.c
+++ b/programs/ssl/ssl_client2.c
@@ -223,7 +223,7 @@
     "    debug_level=%%d      default: 0 (disabled)\n"      \
     "    nbio=%%d             default: 0 (blocking I/O)\n"  \
     "                        options: 1 (non-blocking), 2 (added delays)\n" \
-    "    read_timeout=%%d     default: 0 (no timeout)\n"    \
+    "    read_timeout=%%d     default: 0 ms (no timeout)\n"    \
     "    max_resend=%%d       default: 0 (no resend on timeout)\n" \
     "\n"                                                    \
     USAGE_DTLS                                              \
diff --git a/programs/ssl/ssl_server2.c b/programs/ssl/ssl_server2.c
index 7fc9fa0..bd4d1d1 100644
--- a/programs/ssl/ssl_server2.c
+++ b/programs/ssl/ssl_server2.c
@@ -301,7 +301,7 @@
     "    debug_level=%%d      default: 0 (disabled)\n"      \
     "    nbio=%%d             default: 0 (blocking I/O)\n"  \
     "                        options: 1 (non-blocking), 2 (added delays)\n" \
-    "    read_timeout=%%d     default: 0 (no timeout)\n"    \
+    "    read_timeout=%%d     default: 0 ms (no timeout)\n"    \
     "\n"                                                    \
     USAGE_DTLS                                              \
     USAGE_COOKIES                                           \