travis: Run bootstrap to fix build

autogen.sh isn't enough:

  $ ./autogen.sh
  Gnulib not yet bootstrapped; run ./bootstrap instead.
  The command "./autogen.sh" exited with 1.

Additionally, using bootstrap requires to install autopoint package.

Signed-off-by: Petr Vorel <pvorel@suse.cz>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

.travis.yml

@@ -12,6 +12,7 @@ language: c
 addons:
   apt:
     packages:
+    - autopoint
     - libsdl1.2-dev
     - lzop
     - ovmf
@@ -35,7 +36,7 @@ before_script:
 script:
   # Comments must be outside the command strings below, or the Travis parser
   # will get confused.
-  - ./autogen.sh
+  - ./bootstrap
 
   # Build all selected GRUB targets.
   - for target in $GRUB_TARGETS; do