Fix documentation for QAndroidJniObject

QDoc does not differentiate between the templated and non-templated
versions of the same function.

Change-Id: Ifa5cfcf0780c267e996a64fd76581032126f0247
Reviewed-by: Jerome Pasion <jerome.pasion@digia.com>
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@digia.com>
Reviewed-by: Martin Smith <martin.smith@digia.com>