Branson: provide new versions. (#10926)

* Branson: provide new versions.

+ Also update dependencies (newer version have fewer dependencies).

* fix style issue

var/spack/repos/builtin/packages/branson/package.py

@@ -12,18 +12,25 @@ class Branson(CMakePackage):
     methods for domain decomposition."""
 
     homepage = "https://github.com/lanl/branson"
-    url      = "https://github.com/lanl/branson/archive/1.01.zip"
+    url      = "https://github.com/lanl/branson/archive/0.82.tar.gz"
     git      = "https://github.com/lanl/branson.git"
 
     tags = ['proxy-app']
 
     version('develop', branch='develop')
+    # Version 1.01 is actually deprecated and older than any of the 0.8 series.
+    # However, its entry is left here to reflect older versions of this
+    # spackage.
     version('1.01', 'cf7095a887a8dd7d417267615bd0452a')
+    version('0.82', '7d83d41d0c7ab9c1c906a902165af31182da4604dd0b69aec28d709fe4d7a6ec',
+            preferred=True)
+    version('0.81', '493f720904791f06b49ff48c17a681532c6a4d9fa59636522cf3f9700e77efe4')
+    version('0.8',  '85ffee110f89be00c37798700508b66b0d15de1d98c54328b6d02a9eb2cf1cb8')
 
     depends_on('mpi@2:')
-    depends_on('boost')
+    depends_on('boost', when='@:0.81')
     depends_on('metis')
-    depends_on('parmetis')
+    depends_on('parmetis', when='@:0.82')
 
     root_cmakelists_dir = 'src'
 
@@ -39,5 +46,5 @@ def install(self, spec, prefix):
         mkdir(prefix.bin)
         mkdir(prefix.doc)
         install('spack-build/BRANSON', prefix.bin)
-        install('LICENSE.txt', prefix.doc)
+        install('LICENSE.md', prefix.doc)
         install('README.md', prefix.doc)