fix(rTorrent): prevent extra commas in serialized XML

[kannibalox]

Description

I just happened to notice this while taking tcpdumps between flood and rTorrent, it doesn't appear to have an negative impact (both xmlrpc-c and tinyxml2 just ignore it), but I tracked it down out of curiosity.

Commands for testing:

console.log(value(["foo", "bar"]));
console.log(sParams(["foo", "bar"]));

Before:

<value><array><data><value><string>foo</string></value>,<value><string>bar</string></value></data></array></value>
<params><param><value><string>foo</string></value></param>,<param><value><string>bar</string></value></param></params>

After:

<value><array><data><value><string>foo</string></value><value><string>bar</string></value></data></array></value>
<params><param><value><string>foo</string></value></param><param><value><string>bar</string></value></param></params>

Related Issue

N/A

Screenshots

N/A

Types of changes

• Breaking change (changes that break backward compatibility of public API or CLI - semver MAJOR)
• New feature (non-breaking change which adds functionality - semver MINOR)
• Bug fix (non-breaking change which fixes an issue - semver PATCH)