Set disabled repos before enabled repos

The ordering of disabling/enabling yum repositories matters, and
the yum module was mixing and matching the order. Specifically,
when yum-utils isn't installed, the codepath which uses the yum
python module was incorrectly ordering enabling and disabling.

The preferred order is to disable repositories and then enable them
to prevent clobbering. This was previously discussed in
ansible/ansible#5255 and incompletely addressed in 0cca4a3.

packaging/os/yum.py

@@ -187,10 +187,10 @@ def is_installed(module, repoq, pkgspec, conf_file, qf=def_qf, en_repos=[], dis_
         pkgs = []
         try:
             my = yum_base(conf_file)
-            for rid in en_repos:
-                my.repos.enableRepo(rid)
             for rid in dis_repos:
                 my.repos.disableRepo(rid)
+            for rid in en_repos:
+                my.repos.enableRepo(rid)
                 
             e,m,u = my.rpmdb.matchPackageNames([pkgspec])
             pkgs = e + m
@@ -226,10 +226,10 @@ def is_available(module, repoq, pkgspec, conf_file, qf=def_qf, en_repos=[], dis_
         pkgs = []
         try:
             my = yum_base(conf_file)
-            for rid in en_repos:
-                my.repos.enableRepo(rid)
             for rid in dis_repos:
                 my.repos.disableRepo(rid)
+            for rid in en_repos:
+                my.repos.enableRepo(rid)
 
             e,m,u = my.pkgSack.matchPackageNames([pkgspec])
             pkgs = e + m
@@ -269,10 +269,10 @@ def is_update(module, repoq, pkgspec, conf_file, qf=def_qf, en_repos=[], dis_rep
 
         try:
             my = yum_base(conf_file)
-            for rid in en_repos:
-                my.repos.enableRepo(rid)
             for rid in dis_repos:
                 my.repos.disableRepo(rid)
+            for rid in en_repos:
+                my.repos.enableRepo(rid)
 
             pkgs = my.returnPackagesByDep(pkgspec) + my.returnInstalledPackagesByDep(pkgspec)
             if not pkgs:
@@ -313,10 +313,10 @@ def what_provides(module, repoq, req_spec, conf_file,  qf=def_qf, en_repos=[], d
         pkgs = []
         try:
             my = yum_base(conf_file)
-            for rid in en_repos:
-                my.repos.enableRepo(rid)
             for rid in dis_repos:
                 my.repos.disableRepo(rid)
+            for rid in en_repos:
+                my.repos.enableRepo(rid)
 
             pkgs = my.returnPackagesByDep(req_spec) + my.returnInstalledPackagesByDep(req_spec)
             if not pkgs: