Workaround for Packages/build-deb CI failures

Packages/build-deb CI flows failed on ubuntu-bionic and ubuntu-focal
with the following mismatch in the ServerTest.suggestions unit-test:

```
[ RUN      ] ServerTest.suggestions
../test/server.cpp:715: Failure
Expected equality of these values:
  r->body
    Which is: ...
  removeEOLWhitespaceMarkers(expectedResponse)
    Which is: ...
With diff:
@@ -2,5 +2,5 @@
   {
     \"value\" : \"Ray (movie)\",
-    \"label\" : \"Ray (<b>movie</b>...\",
+    \"label\" : \"Ray (<b>movie</b>)\",
     \"kind\" : \"path\"
       , \"path\" : \"A/Ray_(movie)\"

Test context:
	url: /ROOT/suggest?content=zimfile&term=movie
```

For some reason (probably, a bug), the implementation of
`Xapian::MSet::snippet()` on those platforms decided that a single closing
parenthesis is more than is appropriate for inclusion in the snippet and
replaced it with a (longer) ellipsis.

Taking advantage of the necessity to work around that bug, the
ServerTest.suggestions's functional coverage was enhanced - the
problematic test point was replaced with a new one using a phrase
instead of a single term.

test/server.cpp

@@ -664,17 +664,17 @@ R"EXPECTEDRESPONSE([
 ]
 )EXPECTEDRESPONSE"
     },
-    { /* url: */ "/ROOT/suggest?content=zimfile&term=movie",
+    { /* url: */ "/ROOT/suggest?content=zimfile&term=old%20sun",
 R"EXPECTEDRESPONSE([
   {
-    "value" : "Ray (movie)",
+    "value" : "That Lucky Old Sun",
-    "label" : "Ray (<b>movie</b>)",
+    "label" : "That Lucky <b>Old</b> <b>Sun</b>",
     "kind" : "path"
-      , "path" : "A/Ray_(movie)"
+      , "path" : "A/That_Lucky_Old_Sun"
   },
   {
-    "value" : "movie ",
+    "value" : "old sun ",
-    "label" : "containing 'movie'...",
+    "label" : "containing 'old sun'...",
     "kind" : "pattern"
     //EOLWHITESPACEMARKER
   }