System.IO: String.Compare -> String.Equals

Per the Best Practices for Using Strings at
http://msdn.microsoft.com/en-us/library/dd465121(v=vs.110).aspx

* Use an overload of the String.Equals method to test whether two
strings are equal.
* Use the String.Compare and String.CompareTo methods to sort strings,
not to check for equality.

Author: justinvp

src/System.IO.FileSystem/src/System/IO/Directory.cs

@@ -578,12 +578,12 @@ public static void Move(String sourceDirName, String destDirName)
 
             StringComparison pathComparison = PathInternal.GetComparison();
 
-            if (String.Compare(sourcePath, destPath, pathComparison) == 0)
+            if (String.Equals(sourcePath, destPath, pathComparison))
                 throw new IOException(SR.IO_SourceDestMustBeDifferent);
 
             String sourceRoot = Path.GetPathRoot(sourcePath);
             String destinationRoot = Path.GetPathRoot(destPath);
-            if (String.Compare(sourceRoot, destinationRoot, pathComparison) != 0)
+            if (!String.Equals(sourceRoot, destinationRoot, pathComparison))
                 throw new IOException(SR.IO_SourceDestMustHaveSameRoot);
 
             FileSystem.Current.MoveDirectory(fullsourceDirName, fulldestDirName);

src/System.IO.FileSystem/src/System/IO/DirectoryInfo.cs

@@ -418,13 +418,13 @@ public void MoveTo(String destDirName)
                 fullSourcePath = FullPath + PathHelpers.DirectorySeparatorCharAsString;
 
             StringComparison pathComparison = PathInternal.GetComparison();
-            if (String.Compare(fullSourcePath, fullDestDirName, pathComparison) == 0)
+            if (String.Equals(fullSourcePath, fullDestDirName, pathComparison))
                 throw new IOException(SR.IO_SourceDestMustBeDifferent);
 
             String sourceRoot = Path.GetPathRoot(fullSourcePath);
             String destinationRoot = Path.GetPathRoot(fullDestDirName);
 
-            if (String.Compare(sourceRoot, destinationRoot, pathComparison) != 0)
+            if (!String.Equals(sourceRoot, destinationRoot, pathComparison))
                 throw new IOException(SR.IO_SourceDestMustHaveSameRoot);
 
             FileSystem.Current.MoveDirectory(FullPath, fullDestDirName);