Log Message:
nmh: Update mail/nmh to 1.7.1

pkgsrc changes:
 - Update patch-ca to avoid patching unused by pkgsrc `uninstall-*'
   targets (not needed) and adjust `installdirs' target to create
   `egdir' (`share/examples/nmh')

Changes:
1.7.1
-----
1.7.1 is a patch release for 1.7, and includes fixes to a number of
significant bugs we have discovered since releasing 1.7.  Specifically,
this release includes the following bug fixes:

 - A significant memory leak in scan(1)
 - rcvdist(1) not passing arguments to post(8) correctly
 - Number formatting functions in the format engine were not truncating
   numbers correctly
 - Various fixes to the test suite