branchmap: improve invalid cache message when reading
This factors out the generation of the message. This helps future error reporting
when reading cache for filtered repository.
hgterm,
am, km, mir, msgr, xenl,
colors#8, cols#80, it#8, lines#24, pairs#64,
acsc=``aaffggiijjkkllmmnnooppqqrrssttuuvvwwxxyyzz{{||}}~~,
bel=^G, bold=\E[1m, clear=\E[H\E[2J, cr=\r,
csr=\E[%i%p1%d;%p2%dr, cub=\E[%p1%dD, cub1=\b,
cud=\E[%p1%dB, cud1=\n, cuf=\E[%p1%dC, cuf1=\E[C,
cup=\E[%i%p1%d;%p2%dH, cuu=\E[%p1%dA, cuu1=\E[A,
dch=\E[%p1%dP, dch1=\E[P, dl=\E[%p1%dM, dl1=\E[M,
ed=\E[J, el=\E[K, enacs=\E)0, home=\E[H, ht=\t,
hts=\EH, il=\E[%p1%dL, il1=\E[L, ind=\n,
is2=\E[m\E[?7h\E[4l\E>\E7\E[r\E[?1;3;4;6l\E8, kbs=\b,
kcub1=\EOD, kcud1=\EOB, kcuf1=\EOC, kcuu1=\EOA,
kdch1=\E[3~, kf1=\E[11~, kf10=\E[21~, kf11=\E[23~,
kf12=\E[24~, kf13=\E[25~, kf14=\E[26~, kf15=\E[28~,
kf16=\E[29~, kf17=\E[31~, kf18=\E[32~, kf19=\E[33~,
kf2=\E[12~, kf20=\E[34~, kf3=\E[13~, kf4=\E[14~,
kf5=\E[15~, kf6=\E[17~, kf7=\E[18~, kf8=\E[19~,
kf9=\E[20~, kfnd=\E[1~, kich1=\E[2~, kmous=\E[M,
knp=\E[6~, kpp=\E[5~, kslt=\E[4~, op=\E[m, rc=\E8,
rev=\E[7m, ri=\EM, rmacs=^O, rmcup=\E[2J\E[?47l\E8,
rmir=\E[4l, rmkx=\E[?1l\E>, rmso=\E[m, rmul=\E[m,
rs2=\E[m\E[?7h\E[4l\E>\E7\E[r\E[?1;3;4;6l\E8, sc=\E7,
setab=\E[4%p1%dm, setaf=\E[3%p1%dm, sgr0=\E[m,
smacs=^N, smcup=\E7\E[?47h, smir=\E[4h,
smkx=\E[?1h\E=, smso=\E[7m, smul=\E[4m, tbc=\E[3g,
u6=\E[%i%d;%dR, u7=\E[6n, u8=\E[?1;2c, u9=\E[c,