community/snapcast: rename pre-install file

snapcast-server is the only subpackage which needs a pre-install file.

community/snapcast/snapcast-server.pre-install

-snapcast.pre-install
\ No newline at end of file

community/snapcast/snapcast-server.pre-install

+#!/bin/sh
+
+addgroup -S -g 18 audio 2>/dev/null
+addgroup -S snapcast 2>/dev/null
+adduser -S -D -h /var/lib/snapcast -s /sbin/nologin -G snapcast -g snapcast snapcast 2>/dev/null
+addgroup snapcast audio 2>/dev/null
+
+exit 0

community/snapcast/snapcast.pre-install

-#!/bin/sh
-
-addgroup -S -g 18 audio 2>/dev/null
-addgroup -S snapcast 2>/dev/null
-adduser -S -D -h /var/lib/snapcast -s /sbin/nologin -G snapcast -g snapcast snapcast 2>/dev/null
-addgroup snapcast audio 2>/dev/null
-
-exit 0