Added three new attributes and applied a patch to res_config_ldap.c

Added three new attributes and applied a patch to res_config_ldap.c

attributetype ( AstAccountSubscribeContext
        NAME 'AstAccountSubscribeContext'
        DESC 'Asterisk subscribe context'
        EQUALITY caseIgnoreMatch
        SUBSTR caseIgnoreSubstringsMatch
        SYNTAX 1.3.6.1.4.1.1466.115.121.1.15)

attributetype ( AstAccountIpAddr
        NAME 'AstAccountIpAddr'
        DESC 'Asterisk aaccount IP address'
        EQUALITY caseIgnoreMatch
        SUBSTR caseIgnoreSubstringsMatch
        SYNTAX 1.3.6.1.4.1.1466.115.121.1.15)

attributetype ( AstAccountUserAgent
        NAME 'AstAccountUserAgent'
        DESC 'Asterisk account user context'
        EQUALITY caseIgnoreMatch
        SUBSTR caseIgnoreSubstringsMatch
        SYNTAX 1.3.6.1.4.1.1466.115.121.1.15)

and patch fix_empty_attributes_1.6.1.4_v2.patch

(closes issue #13725)
Reported by: macogeek
Patches:
      fix_empty_attributes_1.6.1.4_v2.patch uploaded by xvisor (license 863)
Tested by: suretec

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@211767 65c4cc65-6c06-0410-ace0-fbb531ad65f3