Don't allow configurability for osxfuse paths.

There's no need to complicate the API. If osxfuse makes a
backwards-incompatible change again, we can add support for it.

mount_config.go

@@ -135,14 +135,6 @@ type MountConfig struct {
 	// default name involving the string 'osxfuse' is used.
 	VolumeName string
 
-	// OS X only.
-	//
-	// OSXFUSELocations sets where to look for OSXFUSE files. The arguments are
-	// all the possible locations. The previous locations are replaced.
-	//
-	// Without this option, OSXFUSELocationV3 and OSXFUSELocationV2 are used.
-	OSXFUSELocations []OSXFUSEPaths
-
 	// Additional key=value options to pass unadulterated to the underlying mount
 	// command. See `man 8 mount`, the fuse documentation, etc. for
 	// system-specific information.
@@ -258,18 +250,22 @@ type OSXFUSEPaths struct {
 	DaemonVar string
 }
 
-// Default paths for OSXFUSE. See OSXFUSELocations.
 var (
-	OSXFUSELocationV3 = OSXFUSEPaths{
+	osxfuseLocations = []OSXFUSEPaths{
+		// v3
+		{
 			DevicePrefix: "/dev/osxfuse",
 			Load:         "/Library/Filesystems/osxfuse.fs/Contents/Resources/load_osxfuse",
 			Mount:        "/Library/Filesystems/osxfuse.fs/Contents/Resources/mount_osxfuse",
 			DaemonVar:    "MOUNT_OSXFUSE_DAEMON_PATH",
-	}
-	OSXFUSELocationV2 = OSXFUSEPaths{
+		},
+
+		// v2
+		{
 			DevicePrefix: "/dev/osxfuse",
 			Load:         "/Library/Filesystems/osxfusefs.fs/Support/load_osxfusefs",
 			Mount:        "/Library/Filesystems/osxfusefs.fs/Support/mount_osxfusefs",
 			DaemonVar:    "MOUNT_FUSEFS_DAEMON_PATH",
+		},
 	}
 )

mount_darwin.go

@@ -17,9 +17,7 @@ var errNoAvail = errors.New("no available fuse devices")
 var errNotLoaded = errors.New("osxfuse is not loaded")
 
 // errOSXFUSENotFound is returned from Mount when the OSXFUSE installation is
-// not detected.
-//
-// Make sure OSXFUSE is installed, or see OSXFUSELocations for customization.
+// not detected. Make sure OSXFUSE is installed.
 var errOSXFUSENotFound = errors.New("cannot locate OSXFUSE")
 
 func loadOSXFUSE(bin string) error {
@@ -136,16 +134,8 @@ func mount(
 	dir string,
 	cfg *MountConfig,
 	ready chan<- error) (dev *os.File, err error) {
-	// get OSXFUSE locations
-	locations := cfg.OSXFUSELocations
-	if locations == nil {
-		locations = []OSXFUSEPaths{
-			OSXFUSELocationV3,
-			OSXFUSELocationV2,
-		}
-	}
-
-	for _, loc := range locations {
+	// Find the version of osxfuse installed on this machine.
+	for _, loc := range osxfuseLocations {
 		if _, err := os.Stat(loc.Mount); os.IsNotExist(err) {
 			// try the other locations
 			continue