Do not add uninstalled SDKs to PATH.

Fixes issue #10 pt1.

.travis.yml

@@ -17,5 +17,8 @@ install:
 
 jobs:
   include:
-    - stage: Test Wrapper
-      script: fish test/wrapper.fish
+    - stage: General Wrapper Tests
+      script: fish test/wrapper.fish
+    - stage: Ticket-specific tests
+      script:
+        - sdk install crash 1.3.0; sdk uninstall crash 1.3.0; fish test/10_zombies_new.fish

conf.d/sdk.fish

@@ -17,8 +17,8 @@ if test -f "$sdkman_init"
         # This is a subshell, SDKMAN! binaries already in path.
     case '*'
         # No SDKMAN! in PATH yet, so add candidate binaries
-        for ITEM in $HOME/.sdkman/candidates/* ;
-            set -gx PATH $PATH $ITEM/current/bin
+        for ITEM in $HOME/.sdkman/candidates/*/current ;
+            set -gx PATH $PATH $ITEM/bin
         end
     end