Add release notes for v2.1.1

Signed-off-by: David Enyeart <enyeart@us.ibm.com>

release_notes/v2.1.1.md

@@ -0,0 +1,62 @@
+v2.1.1 Release Notes - May XX, 2020
+===================================
+
+Fixes
+-----
+
+**FAB-17778: Fix policy support of multiple signatures from single organization**
+
+Fix de-duplication logic to ensure sufficient number of signatures are received to satisfy
+policies that require multiple signatures from the same organization.
+This problem is rare since most users have policies that require signatures from different
+organizations, not policies that require multiple signatures from the same organization.
+
+**FAB-17722: Validate HSM session and get new if invalid**
+
+Previously the pkcs11 code was set to have a session cache and reuse sessions
+if available in cache. If a session went bad (due to connection issues with HSM),
+the session was not evicted from cache and would be reused.
+If all sessions went bad, the client would never be able to recover and keep using bad sessions.
+
+**FAB-17728: Add delay to pkcs11 create session loop**
+
+Previously there was no backoff when attempting to create a new session if one was not
+available in the HSM session cache. This fix introduces a hardcoded backoff of 100ms
+after each attempt up to 10.
+
+**FAB-17784: Clarify error message when legacy chaincode install fails during build**
+
+When a legacy chaincode install fails due to an error building the
+chaincode, the chaincode will remain installed on the peer. This change clarifies
+the error message so that users understand the behavior:
+"chaincode installed to peer but could not build chaincode".
+
+**FAB-17844: Copy symlinks as-is in external builder output**
+
+Previously, the external builder code did es not check for symlinks in build output
+when copying them. This resulted in the resolved files being copied as files
+instead of symlinks. This commit changes the external builder code so that
+it tests for symlinks, and copies them as symlinks instead of copying them as
+files into the destination directory.
+
+**External builder switch from os.Stat to exec.LookPath**
+
+Replace call to os.Stat to check for the presence of the bin/release script with exec.LookPath.
+The LookPath function, when provided with a relative path, will look for the presence of the
+executable and determine if it's executable. On non-unix platforms, it will also handle looking
+for executable suffixes as appropriate.
+
+**FAB-17907: New chaincode lifecycle should ignore previous build failure during install**
+
+When a chaincode build previously failed while installing the chaincode, the new lifecycle
+would not attempt to rebuild the chaincode on the next install attempt, rather the prior
+build error message was returned to the client. This change ensures that the subsequent
+install attempt rebuilds the chaincode.
+
+**FAB-17733: Validate TLS certs during raft consenter addition**
+
+Validate the client/server TLS certs against the orderer organizations while adding a raft consenter.
+
+
+For the full list of changes, refer to the release change log:
+https://github.com/hyperledger/fabric/blob/release-2.1/CHANGELOG.md#v211