rhel: Clarify instructions for RHEL 7.

The rpm build instructions did not clarify what spec files were to be
used for RHEL 7 and its derivatives.  Clarify that you're actually
supposed to use the spec files called "fedora" for RHEL 7 right now.

Update references to Fedora versions to reflect the current release
(23), as neither 16 or 17 are supported releases anymore.

Signed-off-by: Russell Bryant <russell@ovn.org>
Acked-by: Gurucharan Shetty <guru@ovn.org>

Author: russellb

INSTALL.Fedora.md

@@ -5,7 +5,8 @@ This document describes how to build and install Open vSwitch on a Fedora
 Linux host.  If you want to install Open vSwitch on a generic Linux host,
 see [INSTALL.md] instead.
 
-We have tested these instructions with Fedora 16 and Fedora 17.
+We have tested these instructions with Fedora 23. These instructions are also
+used for RHEL 7.x and its derivatives, such as CentOS 7.x.
 
 Building Open vSwitch for Fedora
 --------------------------------
@@ -26,7 +27,7 @@ Fedora.  The command "rpmbuild --showrc" will show the configuration
 for each of those directories. Alternatively, the command "rpm --eval
  '%{_topdir}'" shows the current configuration for the top level
 directory and the command "rpm --eval '%{_sourcedir}'" does the same
-for the sources directory.  On Fedora 17, the default RPM _topdir is
+for the sources directory.  On Fedora 23, the default RPM _topdir is
 $HOME/rpmbuild and the default RPM sources directory is
 $HOME/rpmbuild/SOURCES.
 
@@ -66,17 +67,17 @@ $HOME/rpmbuild/SOURCES.
 
        `rpmbuild -bb --without check rhel/openvswitch-fedora.spec`
 
-5. On Fedora 17, to build the Open vSwitch kernel module, run:
+5. On Fedora 23, to build the Open vSwitch kernel module, run:
 
 	`rpmbuild -bb rhel/openvswitch-kmod-fedora.spec`
 
     You might have to specify a kernel version and/or variants, e.g.:
 
 	```
 	rpmbuild -bb \
-		-D "kversion 2.6.32-131.6.1.el6.x86_64" \
+		-D "kversion 4.3.3-300.fc23.x86_64” \
 		-D "kflavors default debug kdump" \
-		rhel/openvswitch-kmod-rhel6.spec
+		rhel/openvswitch-kmod-fedora.spec
 	```
 
     This produces an "kmod-openvswitch" RPM for each kernel variant,

INSTALL.RHEL.md

@@ -7,6 +7,10 @@ on a generic Linux host, see [INSTALL.md] instead.
 
 We have tested these instructions with RHEL 5.6 and RHEL 6.0.
 
+For RHEL 7.x (or derivatives, such as CentOS 7.x), you should follow
+the instructions in [INSTALL.Fedora.md].  The Fedora spec files are
+used for RHEL 7.x.
+
 Building Open vSwitch for RHEL
 ------------------------------