pkg/pub_semver: remove analyzer warnings

lib/src/version.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library pub_semver.src.version;
 
 import 'dart:math';
 
 import 'package:collection/equality.dart';
 
@@ skipping 104 matching lines @@
 
     try {
       int major = int.parse(match[1]);
       int minor = int.parse(match[2]);
       int patch = int.parse(match[3]);
 
       String preRelease = match[5];
       String build = match[8];
 
       return new Version._(major, minor, patch, preRelease, build, text);
-    } on FormatException catch (ex) {
+    } on FormatException {
       throw new FormatException('Could not parse "$text".');
     }
   }
 
   /// Returns the primary version out of a list of candidates.
   ///
   /// This is the highest-numbered stable (non-prerelease) version. If there
   /// are no stable versions, it's just the highest-numbered version.
   static Version primary(List<Version> versions) {
     var primary;
     for (var version in versions) {
       if (primary == null || (!version.isPreRelease && primary.isPreRelease) ||
           (version.isPreRelease == primary.isPreRelease && version > primary)) {
         primary = version;
       }
     }
     return primary;
   }
 
   /// Splits a string of dot-delimited identifiers into their component parts.
   ///
   /// Identifiers that are numeric are converted to numbers.
   static List _splitParts(String text) {
     return text.split('.').map((part) {
       try {
         return int.parse(part);
-      } on FormatException catch (ex) {
+      } on FormatException {
         // Not a number.
         return part;
       }
     }).toList();
   }
 
   bool operator ==(other) {
     if (other is! Version) return false;
     return major == other.major && minor == other.minor &&
         patch == other.patch &&
@@ skipping 140 matching lines @@
           // Compare two strings.
           return aPart.compareTo(bPart);
         }
       }
     }
 
     // The lists are entirely equal.
     return 0;
   }
 }