Update gemspec: less ::, rename block local for spec

rgeo.gemspec

@@ -1,24 +1,24 @@
-::Gem::Specification.new do |s_|
-  s_.name = "rgeo"
-  s_.summary = "RGeo is a geospatial data library for Ruby."
-  s_.description =
+Gem::Specification.new do |spec|
+  spec.name = "rgeo"
+  spec.summary = "RGeo is a geospatial data library for Ruby."
+  spec.description =
     "RGeo is a geospatial data library for Ruby. It provides an implementation " \
     "of the Open Geospatial Consortium's Simple Features Specification, used by " \
     "most standard spatial/geographic data storage systems such as PostGIS. A " \
     "number of add-on modules are also available to help with writing " \
     "location-based applications using Ruby-based frameworks such as Ruby On Rails."
-  s_.version = "#{::File.read('Version').strip}.nonrelease"
-  s_.author = "Daniel Azuma"
-  s_.email = "dazuma@gmail.com"
-  s_.homepage = "http://github.com/rgeo/rgeo"
-  s_.required_ruby_version = ">= 1.9.3"
-  s_.files = ::Dir.glob("lib/**/*.rb") +
-    ::Dir.glob("ext/**/*.{rb,c,h}") +
-    ::Dir.glob("test/**/*.rb") +
-    ::Dir.glob("*.rdoc") +
+  spec.version = "#{::File.read('Version').strip}.nonrelease"
+  spec.author = "Daniel Azuma"
+  spec.email = "dazuma@gmail.com"
+  spec.homepage = "http://github.com/rgeo/rgeo"
+  spec.required_ruby_version = ">= 1.9.3"
+  spec.files = Dir.glob("lib/**/*.rb") +
+    Dir.glob("ext/**/*.{rb,c,h}") +
+    Dir.glob("test/**/*.rb") +
+    Dir.glob("*.rdoc") +
     ["Version"]
-  s_.extra_rdoc_files = ::Dir.glob("*.rdoc")
-  s_.test_files = ::Dir.glob("test/**/tc_*.rb")
-  s_.platform = ::Gem::Platform::RUBY
-  s_.extensions = ::Dir.glob("ext/*/extconf.rb")
+  spec.extra_rdoc_files = Dir.glob("*.rdoc")
+  spec.test_files = Dir.glob("test/**/tc_*.rb")
+  spec.platform = Gem::Platform::RUBY
+  spec.extensions = Dir.glob("ext/*/extconf.rb")
 end