Fix LICENSE and remove duplicate copyright file

Lemmih, Paolo Martini are the primary authors of cabal-install but were
missing from the list in LICENCE.

cabal-install/LICENSE

-Copyright Isaac Jones 2003-2005.
+Copyright (c) 2003-2007, Isaac Jones, Simon Marlow, Martin Sjögren,
+                         Bjorn Bringert, Krasimir Angelov,
+                         Malcolm Wallace, Ross Patterson,
+                         Lemmih, Paolo Martini
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without

cabal-install/copyright

-Copyright (c) 2003-2005, Isaac Jones, Simon Marlow, Martin Sjögren,
-                         Bjorn Bringert, Krasimir Angelov,
-                         Malcolm Wallace, Ross Patterson
-All rights reserved.
-
-Redistribution and use in source and binary forms, with or without
-modification, are permitted provided that the following conditions are
-met:
-
-    * Redistributions of source code must retain the above copyright
-      notice, this list of conditions and the following disclaimer.
-
-    * Redistributions in binary form must reproduce the above
-      copyright notice, this list of conditions and the following
-      disclaimer in the documentation and/or other materials provided
-      with the distribution.
-
-    * Neither the name of Isaac Jones nor the names of other
-      contributors may be used to endorse or promote products derived
-      from this software without specific prior written permission.
-
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.