Fix .gitignore for vncviewer/ and tests/

We had partial coverage for vncviewer/ already, but fix up the last
pieces.

.gitignore

@@ -11,6 +11,3 @@ CMakeCache.txt
 Makefile
 Makefile.in
 config.h
-
-vncviewer.desktop.in
-vncviewer.desktop

tests/.gitignore

@@ -0,0 +1,6 @@
+conv
+convperf
+decperf
+encperf
+fbperf
+hostport

vncviewer/.gitignore

@@ -0,0 +1,3 @@
+vncviewer
+vncviewer.desktop.in
+vncviewer.desktop