IsEnvTrue and IsEnvFalse should take `True` and `False` as valid values respectively.

Change-Id: Ibca5800c0846a45e3811db76fb5ad46b8a7eb1c1
diff --git a/android/config.go b/android/config.go
index 75d135f..e0eacc3 100644
--- a/android/config.go
+++ b/android/config.go
@@ -813,12 +813,12 @@
 }
 
 func (c *config) IsEnvTrue(key string) bool {
-	value := c.Getenv(key)
+	value := strings.ToLower(c.Getenv(key))
 	return value == "1" || value == "y" || value == "yes" || value == "on" || value == "true"
 }
 
 func (c *config) IsEnvFalse(key string) bool {
-	value := c.Getenv(key)
+	value := strings.ToLower(c.Getenv(key))
 	return value == "0" || value == "n" || value == "no" || value == "off" || value == "false"
 }