Instrumented libraries: update the libnspr4 build script.

There has been a security update in Precise which changed the paths somewhat.

BUG=313751
TBR=glider@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/600793002

Cr-Commit-Position: refs/heads/master@{#296395}

third_party/instrumented_libraries/scripts/libnspr4.sh

@@ -5,4 +5,4 @@
 
 # This script does some preparations before build of instrumented libnspr4.
 
-mv mozilla/nsprpub/* .
+mv nspr/* .