[bug 581] Fix parameter checking if no data-type

Fix bug #581, which reported that the deployment of the simplecharm
failed because the filename parameter was invalid.

This turned out to be an issue introduced with the parameter
type-checking added for R5. This has been fixed, and an integration test
has been added that exercises the simplecharm example.

Signed-off-by: Adam Israel <adam.israel@canonical.com>
diff --git a/tests/charms/layers/simple/config.yaml b/tests/charms/layers/simple/config.yaml
new file mode 100644
index 0000000..51f2ce4
--- /dev/null
+++ b/tests/charms/layers/simple/config.yaml
@@ -0,0 +1,14 @@
+options:
+  string-option:
+    type: string
+    default: "Default Value"
+    description: "A short description of the configuration option"
+  boolean-option:
+    type: boolean
+    default: False
+    description: "A short description of the configuration option"
+  int-option:
+    type: int
+    default: 9001
+    description: "A short description of the configuration option"
+