File _patchinfo of Package patchinfo.21102

<patchinfo incident="21102">
  <issue tracker="bnc" id="1190225">L3: libcares2 hostname validation rejects underscore in CNAME</issue>
  <packager>adamm</packager>
  <rating>important</rating>
  <category>recommended</category>
  <summary>Recommended update for c-ares</summary>
  <description>This update for c-ares fixes the following issue:

- Allow '_' as part of DNS response. (bsc#1190225)
  - 'c-ares' 1.17.2 introduced response validation to prevent a security issue, however it was not listing '_' as a 
    valid character for domain name responses which caused issues when a 'CNAME' referenced a 'SRV' record which 
    contained underscores.
</description>
</patchinfo>