grep: use "found" instead of "filerevmatches" examination for efficiency Before this patch, internal function "display()" of "hg grep" stores whether matching is already found or not into the dictionary "filerevmatches" by "(fn, rev)" tuple as the key. But this is redundant, because: - "filerevmatches" is local variable of "display()", so each "display()" invocations don't affect others - both "fn" and "rev" (gotten from "ctx" argument) are never changed in each "display()" invocations Then, "filerevmatches" should have only one entry at most, and "(fn, rev) in filerevmatches" should be equal to "found". This patch uses "found" instead of "filerevmatches" examination for efficiency.