Remove LICENSE build-artifact, update gitignore

Signed-off-by: Knut Ahlers <knut@ahlers.me>

.gitignore

@@ -1,5 +1,8 @@
-*.t*
+*
-pkg/
+!cockroach.default
-src/
+!cockroach.service
-__pycache__
+!cockroach.sysusers
-update_check.py
+!cockroach.tmpfiles
+!PKGBUILD
+!.SRCINFO
+!update_version.sh

LICENSE

@@ -1,10 +0,0 @@
-Source code in this repository is variously licensed under the Business Source
-License 1.1 (BSL), the CockroachDB Community License (CCL), the MIT license, and
-BSD-style licenses. A copy of each license can be found in the licenses
-directory. Source code in a given file is licensed under the BSL and the
-copyright belongs to The Cockroach Authors unless otherwise noted at the
-beginning of the file.
-
-Running `make` will produce a binary that includes CCL-licensed code and is thus
-subject to the terms of the CCL. To produce a binary that is free of CCL-
-licensed code, run `make buildoss`.