Remove default labels from fully covered switch statements.

Allow compilers to warn when new enum values are added, making
switches no-longer fully-covered.

Source/cmCTest.cxx

@@ -217,8 +217,6 @@ int cmCTest::HTTPRequest(std::string url, HTTPMethod method,
         url += "?" + fields;
         }
       break;
-    default:
-      break;
     }
 
   ::curl_easy_setopt(curl, CURLOPT_URL, url.c_str());

Source/cmLocalGenerator.cxx

@@ -2283,7 +2283,6 @@ bool cmLocalGenerator::GetShouldUseOldFlags(bool shared,
         case cmPolicies::REQUIRED_IF_USED:
         case cmPolicies::REQUIRED_ALWAYS:
         case cmPolicies::NEW:
-        default:
           return false;
         }
       }

Source/cmMakefile.cxx

@@ -3365,7 +3365,6 @@ std::string cmMakefile::GetModulesFile(const char* filename) const
         case cmPolicies::REQUIRED_IF_USED:
         case cmPolicies::REQUIRED_ALWAYS:
         case cmPolicies::NEW:
-        default:
           result = moduleInCMakeRoot;
           break;
         }

Source/cmNewLineStyle.cxx

@@ -76,8 +76,6 @@ const std::string cmNewLineStyle::GetCharacters() const
       return "\n";
     case CRLF:
       return "\r\n";
-    default:
-      ;
     }
   return "";
 }

Source/cmTargetLinkLibrariesCommand.cxx

@@ -70,7 +70,6 @@ bool cmTargetLinkLibrariesCommand
                                   GetRequiredPolicyError(cmPolicies::CMP0016);
           break;
         case cmPolicies::NEW:  // NEW behavior prints the error.
-        default:
           break;
         }
       }