[system-administrators-guide] typo

[stephenw]

commit b3c35411edfe313a1f2aa2126ec7a064708675fc
Author: Stephen Wadeley <swadeley at redhat.com>
Date:   Mon Dec 15 09:55:37 2014 +0100

    typo

 en-US/Configuring_PTP_Using_ptp4l.xml |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/en-US/Configuring_PTP_Using_ptp4l.xml b/en-US/Configuring_PTP_Using_ptp4l.xml
index ea6aab9..ba5e354 100644
--- a/en-US/Configuring_PTP_Using_ptp4l.xml
+++ b/en-US/Configuring_PTP_Using_ptp4l.xml
@@ -71,7 +71,7 @@ Hardware Transmit Timestamp Modes:
 Hardware Receive Filter Modes:
         none                  (HWTSTAMP_FILTER_NONE)
         all                   (HWTSTAMP_FILTER_ALL)</screen>
-  Where <replaceable>eth3</replaceable> is the interface you want to check.
+  Where <replaceable>em3</replaceable> is the interface you want to check.
 </para>
   <para>
     For software time stamping support, the parameters list