Check upstream GPG signatures in %prep

Many years ago, the GPG signature file was included in the source list¹.
A compromise at kernel.org caused the tarballs to move to googlecode.com
for a number of releases and the signatures were not provided in an
easily downloaded format².  When the source location was moved back to
kernel.org, the signature file had already been removed from the spec
file and was not re-added³.

There is an effort underway to make GPG signature verification a
requirement when upstream provides signatures⁴.  Regardless of whether
this becomes a requirement in the packaging guidelines, verification of
upstream signatures makes good sense.  It also makes the process easier
for git package maintainers, who are (or should be ;) doing this
manually for each upstream git release.

While adding the signatures to the source list, all non-upstream source
files were moved to Source10 and above.  This should make it easier to
add new upstream source files in the future, avoiding the need for
tedious (and error-prone) renumbering of existing sources.

Remove the unused entry for Patch14 also.

¹ ea3f253 Include gpg signature for tarball in SRPM (2011-08-26)
² c57f383 Update to 1.7.9.1 (2012-02-15)
³ b741f45 Change source URLs, as googlecode doesn't have up-to-date
           tarballs (2014-06-10)
⁴ https://fedorahosted.org/fpc/ticket/610
  https://fedoraproject.org/wiki/PackagingDrafts:GPGSignatures
  https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org/thread/2TBK4LLNRH73QJQSXWFPCQYHGTSJ3C7P/

.gitignore

@@ -1,5 +1,7 @@
 *~
+*.gpg
 *.rpm
+*.sign
 *.tar.xz
 /.build*.log
 /git-*/