The changes in #1512 introduced a regression when a hash value is not
explicitly passed:

```
Puppet Server Error: Evaluation Error: Error while evaluating a Function Call, failed to coerce org.jruby.RubySymbol to java.lang.String
```

Fixes #1528

When calling `postgresql::default()` with a name that has no corresponding
parameter, the function returns the string
"postgresql::globals::<parameter-name>" which is probably not intended
given the comment above the code.

The usage of pick seems to indicate that an exception should be raised
when a parameter is not found in `params` nor `globals.pp`, so adjust
the code accordingly.

`postgresql::params` inherits from `postgresql::globals` so any variable
defined in `postgresql::globals` can be accessed by reading it from
`postgresql::params`, making it redundant to check both.
diff --git a/functions/default.pp b/functions/default.pp
index e36610b..41b5006 100644
--- a/functions/default.pp
+++ b/functions/default.pp
@@ -8,8 +8,7 @@ function postgresql::default(
 ) {
   include postgresql::params

-  #search for the variable name in params first
-  #then fall back to globals if not found
-  pick(getvar("postgresql::params::${parameter_name}"),
-       getvar("postgresql::globals::${parameter_name}"))
+  # Search for the variable name in params.
+  # params inherits from globals, so it will also catch these variables.
+  pick(getvar("postgresql::params::${parameter_name}"))
 }

Fix the `postgresql::postgresql_password()` function

Fix `postgresql::default()` return value for unknown parameters

Release prep v10.0.1