Replace short field names with more descriptive ones.

The decision to change the name of these fields came from reading the code
further down in the scope and not being clear what `c.c` means.

plumbing/transport/http/common.go

@@ -91,9 +91,9 @@ func advertisedReferences(ctx context.Context, s *session, serviceName string) (
 }
 
 type client struct {
-	c          *http.Client
+	client     *http.Client
 	transports *lru.Cache
-	m          sync.RWMutex
+	mutex      sync.RWMutex
 }
 
 // ClientOptions holds user configurable options for the client.
@@ -147,7 +147,7 @@ func NewClientWithOptions(c *http.Client, opts *ClientOptions) transport.Transpo
 		}
 	}
 	cl := &client{
-		c: c,
+		client: c,
 	}
 
 	if opts != nil {
@@ -234,10 +234,10 @@ func newSession(c *client, ep *transport.Endpoint, auth transport.AuthMethod) (*
 		// if the client wasn't configured to have a cache for transports then just configure
 		// the transport and use it directly, otherwise try to use the cache.
 		if c.transports == nil {
-			tr, ok := c.c.Transport.(*http.Transport)
+			tr, ok := c.client.Transport.(*http.Transport)
 			if !ok {
 				return nil, fmt.Errorf("expected underlying client transport to be of type: %s; got: %s",
-					reflect.TypeOf(transport), reflect.TypeOf(c.c.Transport))
+					reflect.TypeOf(transport), reflect.TypeOf(c.client.Transport))
 			}
 
 			transport = tr.Clone()
@@ -258,20 +258,20 @@ func newSession(c *client, ep *transport.Endpoint, auth transport.AuthMethod) (*
 			transport, found = c.fetchTransport(transportOpts)
 
 			if !found {
-				transport = c.c.Transport.(*http.Transport).Clone()
+				transport = c.client.Transport.(*http.Transport).Clone()
 				configureTransport(transport, ep)
 				c.addTransport(transportOpts, transport)
 			}
 		}
 
 		httpClient = &http.Client{
 			Transport:     transport,
-			CheckRedirect: c.c.CheckRedirect,
-			Jar:           c.c.Jar,
-			Timeout:       c.c.Timeout,
+			CheckRedirect: c.client.CheckRedirect,
+			Jar:           c.client.Jar,
+			Timeout:       c.client.Timeout,
 		}
 	} else {
-		httpClient = c.c
+		httpClient = c.client
 	}
 
 	s := &session{

plumbing/transport/http/common_test.go

@@ -46,7 +46,7 @@ func (s *UploadPackSuite) TestNewClient(c *C) {
 	cl := &http.Client{Transport: roundTripper}
 	r, ok := NewClient(cl).(*client)
 	c.Assert(ok, Equals, true)
-	c.Assert(r.c, Equals, cl)
+	c.Assert(r.client, Equals, cl)
 }
 
 func (s *ClientSuite) TestNewBasicAuth(c *C) {

plumbing/transport/http/transport.go

@@ -14,21 +14,21 @@ type transportOptions struct {
 }
 
 func (c *client) addTransport(opts transportOptions, transport *http.Transport) {
-	c.m.Lock()
+	c.mutex.Lock()
 	c.transports.Add(opts, transport)
-	c.m.Unlock()
+	c.mutex.Unlock()
 }
 
 func (c *client) removeTransport(opts transportOptions) {
-	c.m.Lock()
+	c.mutex.Lock()
 	c.transports.Remove(opts)
-	c.m.Unlock()
+	c.mutex.Unlock()
 }
 
 func (c *client) fetchTransport(opts transportOptions) (*http.Transport, bool) {
-	c.m.RLock()
+	c.mutex.RLock()
 	t, ok := c.transports.Get(opts)
-	c.m.RUnlock()
+	c.mutex.RUnlock()
 	if !ok {
 		return nil, false
 	}