[wwwdocs] bugs/index.html: remove explanation of major releases

[Gerald Pfeifer]

We adopted a numbering scheme that clearly shows major releases
as such, so this bit has become unnecessary (and was outdated for
all pratical purposes).

Applied.

Gerald

Index: index.html
===================================================================
RCS file: /cvs/gcc/wwwdocs/htdocs/bugs/index.html,v
retrieving revision 1.120
diff -u -r1.120 index.html
--- index.html	25 Nov 2017 19:01:33 -0000	1.120
+++ index.html	1 Dec 2017 01:17:15 -0000
@@ -676,13 +676,6 @@
 <a href="https://gcc.gnu.org/onlinedocs/gcc/Compatibility.html">compatibility
 section</a> of the GCC manual.</p>
 
-<p>Remark: A major release is designated by a change to the first or second
-component of the two- or three-part version number.  A minor (bug-fix)
-release is designated by a change to the third component only.  Thus GCC
-3.2 and 3.3 are major releases, while 3.3.1 and 3.3.2 are bug-fix releases
-for GCC 3.3.  With the 3.4 series we are introducing a new naming scheme;
-the first release of this series is 3.4.0 instead of just 3.4.</p>
-
 <h4>Standard conformance</h4>
 
 <p>With each release, we try to make G++ conform closer to the <a href=