.travis.yml: disable linux-user build for gcov

Currently the default testing doesn't exercise the linux-user builds
so there is no point spending time building them. We may want to
enable a separate gcov build once linux-user testing is re-enabled
although it's likely to report very low coverage.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

.travis.yml

@@ -74,7 +74,7 @@ matrix:
     - env: CONFIG=""
       compiler: clang
     # gprof/gcov are GCC features
-    - env: CONFIG="--enable-gprof --enable-gcov --disable-pie"
+    - env: CONFIG="--enable-gprof --enable-gcov --disable-pie --disable-linux-user"
       compiler: gcc
     # We manually include builds which we disable "make check" for
     - env: CONFIG="--enable-debug --enable-tcg-interpreter"