make API specs more organized and readable

spec/requests/api/issues_spec.rb

@@ -9,12 +9,14 @@ describe Gitlab::API do
   before { project.add_access(user, :read) }
 
   describe "GET /issues" do
+    context "when unauthenticated" do
       it "should return authentication error" do
         get api("/issues")
         response.status.should == 401
       end
+    end
 
-    describe "authenticated GET /issues" do
+    context "when authenticated" do
       it "should return an array of issues" do
         get api("/issues", user)
         response.status.should == 200

spec/requests/api/projects_spec.rb

@@ -9,12 +9,14 @@ describe Gitlab::API do
   before { project.add_access(user, :read) }
 
   describe "GET /projects" do
+    context "when unauthenticated" do
       it "should return authentication error" do
         get api("/projects")
         response.status.should == 401
       end
+    end
 
-    describe "authenticated GET /projects" do
+    context "when authenticated" do
       it "should return an array of projects" do
         get api("/projects", user)
         response.status.should == 200

spec/requests/api/users_spec.rb

@@ -6,12 +6,14 @@ describe Gitlab::API do
   let(:user) { Factory :user }
 
   describe "GET /users" do
+    context "when unauthenticated" do
       it "should return authentication error" do
         get api("/users")
         response.status.should == 401
       end
+    end
 
-    describe "authenticated GET /users" do
+    context "when authenticated" do
       it "should return an array of users" do
         get api("/users", user)
         response.status.should == 200