t5534: fix misleading grep invocation

It seems to be a little-known feature of `grep` (and it certainly came as a surprise to this here developer who believed to know the Unix tools pretty well) that multiple patterns can be passed in the same command-line argument simply by separating them by newlines. Watch, and learn: $ printf '1\n2\n3\n' | grep "$(printf '1\n3\n')" 1 3 That behavior also extends to patterns passed via `-e`, and it is not modified by passing the option `-E` (but trying this with -P issues the error "grep: the -P option only supports a single pattern"). It seems that there are more old Unix hands who are surprised by this behavior, as grep invocations of the form grep "$(git rev-parse A B) C" file were introduced in a85b377d041 (push: the beginning of "git push --signed", 2014-09-12), and later faithfully copy-edited in b9459019bbb (push: heed user.signingkey for signed pushes, 2014-10-22). Please note that the output of `git rev-parse A B` separates the object IDs via *newlines*, not via spaces, and those newlines are preserved because the interpolation is enclosed in double quotes. As a consequence, these tests try to validate that the file contains either A's object ID, or B's object ID followed by C, or both. Clearly, however, what the test wanted to see is that there is a line that contains all of them. This is clearly unintended, and the grep invocations in question really match too many lines. Fix the test by avoiding the newlines in the patterns. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>