Remove unused functions

The function ex_varassign is never called. The function ex_lvalue
is only called by ex_varassign.

beets/util/functemplate.py

@@ -58,11 +58,6 @@ class Environment:
 # Code generation helpers.
 
 
-def ex_lvalue(name):
-    """A variable load expression."""
-    return ast.Name(name, ast.Store())
-
-
 def ex_rvalue(name):
     """A variable store expression."""
     return ast.Name(name, ast.Load())
@@ -75,15 +70,6 @@ def ex_literal(val):
     return ast.Constant(val)
 
 
-def ex_varassign(name, expr):
-    """Assign an expression into a single variable. The expression may
-    either be an `ast.expr` object or a value to be used as a literal.
-    """
-    if not isinstance(expr, ast.expr):
-        expr = ex_literal(expr)
-    return ast.Assign([ex_lvalue(name)], expr)
-
-
 def ex_call(func, args):
     """A function-call expression with only positional parameters. The
     function may be an expression or the name of a function. Each