hammer now only supports CentOS 7 and Ubuntu 14.04

Signed-off-by: Loic Dachary <loic@dachary.org>

diff --git a/distros/supported/centos_7.0.yaml b/distros/supported/centos_7.0.yaml
new file mode 120000 (symlink)
index 0000000..f512e12
--- /dev/null
+++ b/distros/supported/centos_7.0.yaml
@@ -0,0 +1 @@
+../all/centos_7.0.yaml
\ No newline at end of file

diff --git a/distros/supported/debian_7.0.yaml b/distros/supported/debian_7.0.yaml
deleted file mode 120000 (symlink)
index 2a14a98..0000000
--- a/distros/supported/debian_7.0.yaml
+++ /dev/null
@@ -1 +0,0 @@
-../all/debian_7.0.yaml
\ No newline at end of file

diff --git a/distros/supported/ubuntu_12.04.yaml b/distros/supported/ubuntu_12.04.yaml
deleted file mode 120000 (symlink)
index 56160b8..0000000
--- a/distros/supported/ubuntu_12.04.yaml
+++ /dev/null
@@ -1 +0,0 @@
-../all/ubuntu_12.04.yaml
\ No newline at end of file