ci: use fedora 25 instead of fedora23

Fedora 23 is no longer supported. Current release is Fedora 25

Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>
diff --git a/ci/Dockerfile/fedora23.x86_64 b/ci/Dockerfile/fedora23.x86_64
deleted file mode 120000
index 5322ce7..0000000
--- a/ci/Dockerfile/fedora23.x86_64
+++ /dev/null
@@ -1 +0,0 @@
-fedora23
\ No newline at end of file
diff --git a/ci/Dockerfile/fedora23 b/ci/Dockerfile/fedora25
similarity index 96%
rename from ci/Dockerfile/fedora23
rename to ci/Dockerfile/fedora25
index ed50956..9414efc 100644
--- a/ci/Dockerfile/fedora23
+++ b/ci/Dockerfile/fedora25
@@ -1,4 +1,4 @@
-FROM fedora:23
+FROM fedora:25
 RUN dnf -y remove vim-minimal
 RUN dnf -y install gcc-c++ flex bison git ctags cscope expat-devel patch zlib-devel zlib-static texinfo perl-bignum "perl(XML::Simple)" "perl(YAML)" "perl(XML::SAX)" "perl(Fatal)" "perl(Thread::Queue)" "perl(Env)" "perl(XML::LibXML)" "perl(Digest::SHA1)" libxml2-devel libxslt "perl(ExtUtils::MakeMaker)"
 RUN dnf -y install which wget unzip tar cpio python bzip2 bc vim redhat-lsb-core
diff --git a/ci/Dockerfile/fedora25.x86_64 b/ci/Dockerfile/fedora25.x86_64
new file mode 120000
index 0000000..c6db8fc
--- /dev/null
+++ b/ci/Dockerfile/fedora25.x86_64
@@ -0,0 +1 @@
+fedora25
\ No newline at end of file