gitweb: Add charset info to "raw" output of 'text/plain' blobs
Earlier "blob_plain" view sent "charset=utf-8" only when gitweb guessed the content type to be text by reading from it, and not when the MIME type was obtained from /etc/mime.types, or when gitweb couldn't guess mimetype and used $default_blob_plain_mimetype.
This fixes the bug by always add charset info from $default_text_plain_charset (if it is defined) to "raw" (a=blob_plain) output for 'text/plain' blobs.
Generating information for Content-Type: header got separated into blob_contenttype() subroutine; adding charset info in a special case was removed from blob_mimetype(), which now should return mimetype only.
While at it cleanup code a bit: put subroutine parameter initialization first, make error message more robust (when $file_name is not defined) if more cryptic, remove unnecessary '"' around variable ("$var" -> $var).
Signed-off-by: Jakub Narebski <firstname.lastname@example.org> Signed-off-by: Junio C Hamano <email@example.com>