documentation: Updated the manual revision history tables.

Added an entry for the 1.8 release stating that the release
is slated for sometime in 2015.

(From yocto-docs rev: 9799a7848f24024048eae0cbed470a2be4b4b879)

Signed-off-by: Scott Rifenbark <scott.m.rifenbark@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/adt-manual/adt-manual.xml

@@ -81,6 +81,11 @@
                 <date>October 2014</date>
                 <revremark>Released with the Yocto Project 1.7 Release.</revremark>
             </revision>
+            <revision>
+                <revnumber>1.8</revnumber>
+                <date>Sometime in 2015</date>
+                <revremark>Released with the Yocto Project 1.8 Release.</revremark>
+            </revision>
        </revhistory>
 
     <copyright>

documentation/bsp-guide/bsp-guide.xml

@@ -93,6 +93,11 @@
                 <date>October 2014</date>
                 <revremark>Released with the Yocto Project 1.7 Release.</revremark>
             </revision>
+            <revision>
+                <revnumber>1.8</revnumber>
+                <date>Sometime in 2015</date>
+                <revremark>Released with the Yocto Project 1.8 Release.</revremark>
+            </revision>
         </revhistory>
 
     <copyright>

documentation/dev-manual/dev-manual.xml

@@ -71,6 +71,11 @@
                 <date>October 2014</date>
                 <revremark>Released with the Yocto Project 1.7 Release.</revremark>
             </revision>
+            <revision>
+                <revnumber>1.8</revnumber>
+                <date>Sometime in 2015</date>
+                <revremark>Released with the Yocto Project 1.8 Release.</revremark>
+            </revision>
         </revhistory>
 
     <copyright>

documentation/kernel-dev/kernel-dev.xml

@@ -56,6 +56,11 @@
                 <date>October 2014</date>
                 <revremark>Released with the Yocto Project 1.7 Release.</revremark>
             </revision>
+            <revision>
+                <revnumber>1.8</revnumber>
+                <date>Sometime in 2015</date>
+                <revremark>Released with the Yocto Project 1.8 Release.</revremark>
+            </revision>
         </revhistory>
 
     <copyright>

documentation/profile-manual/profile-manual.xml

@@ -56,6 +56,11 @@
                 <date>October 2014</date>
                 <revremark>Released with the Yocto Project 1.7 Release.</revremark>
             </revision>
+            <revision>
+                <revnumber>1.8</revnumber>
+                <date>Sometime in 2015</date>
+                <revremark>Released with the Yocto Project 1.8 Release.</revremark>
+            </revision>
         </revhistory>
 
     <copyright>

documentation/ref-manual/ref-manual.xml

@@ -87,6 +87,11 @@
                 <date>October 2014</date>
                 <revremark>Released with the Yocto Project 1.7 Release.</revremark>
             </revision>
+            <revision>
+                <revnumber>1.8</revnumber>
+                <date>Sometime in 2015</date>
+                <revremark>Released with the Yocto Project 1.8 Release.</revremark>
+            </revision>
         </revhistory>
 
     <copyright>