HowToReleaseLLVM: Add information about dot releases

Based on the following discussion:
http://llvm.1065342.n5.nabble.com/LLVM-3-4-stable-releases-td65005.html

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200772 91177308-0d34-0410-b5e6-96231b3b80d8

docs/HowToReleaseLLVM.rst

@@ -22,12 +22,15 @@ create the binary packages, please refer to the :doc:`ReleaseProcess` instead.
 Release Timeline
 ================
 
-LLVM is released on a time based schedule --- roughly every 6 months.  We do
-not normally have dot releases because of the nature of LLVM's incremental
-development philosophy.  That said, the only thing preventing dot releases for
-critical bug fixes from happening is a lack of resources --- testers,
-machines, time, etc.  And, because of the high quality we desire for LLVM
-releases, we cannot allow for a truncated form of release qualification.
+LLVM is released on a time based schedule --- with major releases roughly
+every 6 months.  In between major releases there may be dot releases.
+The release manager will determine if and when to make a dot release based
+on feedback from the community.  Typically, dot releases should be made if
+there are large number of bug-fixes in the stable branch or a critical bug
+has been discovered that affects a large number of users.
+
+Unless otherwise stated, dot releases will follow the same procedure as
+major releases.
 
 The release process is roughly as follows:
 
@@ -51,6 +54,10 @@ The release process is roughly as follows:
 
 * Finally, release!
 
+The release process will be accelerated for dot releases.  If the first round
+of testing finds no critical bugs and no regressions since the last major release,
+then additional rounds of testing will not be required.
+
 Release Process
 ===============
 
@@ -352,6 +359,8 @@ Below are the rules regarding patching the release branch:
 #. During the remaining rounds of testing, only patches that fix critical
    regressions may be applied.
 
+#. For dot releases all patches must mantain both API and ABI compatibility with
+   the previous major release.  Only bugfixes will be accepted.
 Release Final Tasks
 -------------------