build_abi: add build/ to the path for error msg

Change-Id: I5328a49e8f0e6081f7436f67bdd2cd97c3d949d8
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
diff --git a/build_abi.sh b/build_abi.sh
index e612286..d276c50 100755
--- a/build_abi.sh
+++ b/build_abi.sh
@@ -46,7 +46,7 @@
 # ensure that abigail is present in path
 if ! ( hash abidiff 2>/dev/null); then
     echo "ERROR: libabigail is not found in \$PATH at all!"
-    echo "Have you run abi/bootstrap and followed the instructions?"
+    echo "Have you run build/abi/bootstrap and followed the instructions?"
     exit 1
 fi
 
@@ -54,7 +54,7 @@
 if ! ( version_greater_than "$(abidiff --version | awk '{print $2}')"  \
 			    "1.6.0" ); then
     echo "ERROR: no suitable libabigail (>= 1.6.0) in \$PATH."
-    echo "Have you run abi/bootstrap and followed the instructions?"
+    echo "Have you run build/abi/bootstrap and followed the instructions?"
     exit 1
 fi