matched value control parsing issues (ITS#3208)

[ando@sys-net.it]

Full_Name: Pierangelo Masarati
Version: HEAD, 2.2
OS: Linux (irrelevant)
URL: ftp://ftp.openldap.org/incoming/
Submission from: (NULL) (131.175.154.56)


matchedValue control is parsed incorrectly on the client's side; for instance, a
search with '-E!mv=(ou:caseExactMatch:=People)' yields "matching rule not
recognized" because the first char of the matching rule is parsed incorrectly. 
A search with
'-E!mv=ou:caseExactMatch:=People' is parsed correctly (essentially because a
totally different portion of code is used), but this allows the ":dn" portion of
the extensible filter to be used, which is not allowed in the control.

In any case, event he second search does not return the expected result, but
this is another issue, which will be submitted separately.