Avoid msrest version 0.4.15 for Azure modules.

This version has known regressions preventing modules such as
azure_rm_dnsrecordset from working.

(cherry picked from commit e167c9338c)

packaging/requirements/requirements-azure.txt

@@ -6,6 +6,7 @@ azure-mgmt-storage>=1.2.0,<2
 azure-mgmt-resource>=1.1.0,<2
 azure-storage>=0.35.1,<0.36
 azure-cli-core>=2.0.12,<3
+msrest!=0.4.15
 msrestazure>=0.4.11,<0.5
 azure-mgmt-dns>=1.0.1,<2
 azure-mgmt-keyvault>=0.40.0,<0.41