Fix quoting bug in redhat and ubuntu

[lawsontyler]

Ansible needs to be valid YAML first. By using double-quotes in the comparison, it looks like the YAML string is finished & has a bunch of trailing garbage, which causes this Ansible error:

TASK [ansible-couchbase-server : include] **************************************
fatal: [couchbase-host]: FAILED! => {"reason": "We were unable to read either as JSON nor YAML, these are the errors we got from each:\nJSON: Expecting value: line 1 column 1 (char 0)\n\nSyntax Error while loading YAML.\n  did not find expected key\n\nThe error appears to be in '/[REDACTED]/.ansible/roles/ansible-couchbase-server/tasks/install/redhat.yml': line 49, column 63, but may\nbe elsewhere in the file depending on the exact syntax problem.\n\nThe offending line appears to be:\n\n  yum:\n    name: \"couchbase-server{% if couchbase_server_edition == \"community\" %}-community{% endif %}-{{ couchbase_server_version }}\"\n                                                              ^ here\nWe could be wrong, but this one looks like it might be an issue with\nmissing quotes. Always quote template expression brackets when they\nstart a value. For instance:\n\n    with_items:\n      - {{ foo }}\n\nShould be written as:\n\n    with_items:\n      - \"{{ foo }}\"\n"}

Single quotes fix this issue & the install works as expected.