Upgrade bundled curl to version 7.49.1.

Delete most of the curl patches since they are no longer necessary.
The only needed patch is to produce a library with the expected name
when building on Windows.

Update the curl copyright info in LICENSE.

These curl CVEs have been fixed since 7.19.7:
CVE-2010-0734
CVE-2011-2192
CVE-2013-2174
CVE-2014-3143
CVE-2014-3144
CVE-2014-3145
CVE-2014-3148
CVE-2014-8150
CVE-2015-3153
CVE-2016-0755
Whether any of these affect the OpenOffice usage of curl is not known. 
OpenOffice only uses curl to access ftp:// URLs, which is likely to be
only rarely done.