travis: Print context info for failed qemu-arm.

Author: dpgeorge

.travis.yml

@@ -41,4 +41,4 @@ after_success:
 
 after_failure:
   - (cd tests && for exp in *.exp; do testbase=$(basename $exp .exp); echo -e "\nFAILURE $testbase"; diff -u $testbase.exp $testbase.out; done)
-  - (grep "FAIL" qemu-arm/build/console.out)
+  - (grep -C 2 "FAIL" qemu-arm/build/console.out)