Mail reader sampler: When Number of messages to retrieve is superior to 1, Number of samples should only show 1 not the number of messages retrieved

**sergio** ([Bug 56539](https://bz.apache.org/bugzilla//show_bug.cgi?id=56539&redirect=false)):
Suppose to use IMAP and to set two messages to downloads.

When you run the test, Results tree shows you a sample holding two leaves (one for each message).
It looks like it were an HTML page holding 2 different component, which is very reasonable.

BUT, if you go to the "Aggregate Report" and "Summary Report" you will see 2 different operations, each with its own time.

Again, if you save the results to a .jtl file, only one results is saved, that holds the total time (which is the expected behaviour).

THis happens only when downloading more than 1 message in a single sample.
Java: Java(TM) SE Runtime Environment (build 1.7.0_55-b13).

Created attachment [IMAP_error.jmx](https://apache.github.io/jmeter-bugzilla-attachments/39/56539/31635/IMAP_error.jmx): JMX script showing the behaviour

Severity: normal
OS: All