tesstrain.sh: Only fall back to default Latin fonts if none were provided

The --fontlist argument to tesstrain.sh was always ignored, even if
the language had no specific fonts specified in language-specific.sh.

Change this behaviour so the --fontlist argument is used if no specifc
fonts are selected by language-specific.sh.

Author: nickjwhite

training/language-specific.sh

@@ -794,7 +794,7 @@ set_lang_specific_parameters() {
   local lang=$1
   # The default text location is now given directly from the language code.
   TEXT_CORPUS="${FLAGS_webtext_prefix}/${lang}.corpus.txt"
-  FONTS=( "${LATIN_FONTS[@]}" )
+  test -z "$FONTS" && FONTS=( "${LATIN_FONTS[@]}" )
   FILTER_ARGUMENTS=""
   WORDLIST2DAWG_ARGUMENTS=""
   # These dawg factors represent the fraction of the corpus not covered by the

training/tesstrain_utils.sh

@@ -16,10 +16,6 @@
 #
 # USAGE: source tesstrain_utils.sh
 
-FONTS=(
-    "Arial" \
-    "Times New Roman," \
-)
 if [ "$(uname)" == "Darwin" ];then
     FONTS_DIR="/Library/Fonts/"
 else