Remove duplicate ICU package (#1837)

* Remove duplicate ICU package

* Ignore deleted files during flake8 tests

* Rename Boost ICU variant

var/spack/repos/builtin/packages/icu4c/package.py

@@ -27,8 +27,9 @@
 
 class Icu4c(Package):
     """ICU is a mature, widely used set of C/C++ and Java libraries providing
-       Unicode and Globalization support for software applications.
-    """
+    Unicode and Globalization support for software applications. ICU4C is the
+    C/C++ interface."""
+
     homepage = "http://site.icu-project.org/"
     url      = "http://download.icu-project.org/files/icu4c/57.1/icu4c-57_1-src.tgz"
 
@@ -40,10 +41,9 @@ def url_for_version(self, version):
             base_url, version, version.underscored)
 
     def install(self, spec, prefix):
-        cd('source')
+        with working_dir('source'):
+            configure('--prefix={0}'.format(prefix))
 
-        configure('--prefix={0}'.format(prefix))
-
-        make()
-        make('check')
-        make('install')
+            make()
+            make('check')
+            make('install')